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        검색결과 44

        2.
        2018.05 구독 인증기관·개인회원 무료
        Roller-compacted concrete (RCC) has been widely used for construction of pavements [1]. The strength of RCCP can be obtained from not only hydration of binder but also the aggregate interlock resulted from roller-compaction [2]. For this reason, RCCP normally achieves higher strength compared to conventional concrete pavement with similar cement content. Even though RCCP can be provided a good structural performance, it has been difficult to verify the long-term performance though actual field construction. Therefore, this study aimed to investigate the fatigue characteristics and crack development in RCCP based on full-scale fatigue test and accelerated pavement test. In case of full-scale fatigue tests, fatigue behavior was evaluated by using 1 m × 1 m dimensional RCC slab specimens obtained from the field in order to consider the field variability. Fatigue equation derived from this study shows that the number of load repetitions which causes fatigue failure at the same stress level is slightly larger than that of PCA fatigue equation. In order to evaluate the performance of RCCP, two phases of accelerated pavement test (APT) were conducted. In phase one, the performance of RCCP at two different strengths (35.6 and 30.4 MPa) was evaluated. In phase two, the performance of RCCP with different thickness (5, 7.5 and 10 cm) was investigated. The number of load repetition of fatigue crack occurrence in each section was compared to the estimated fatigue failure determined from fatigue equation of RCCP. The crack development in each section was compared to the AASHTO crack model for JPCP. Overall, it was confirmed that RCCP has equal or better performance compared to JPCP the estimation in term of fatigue cracking. The fatigue equation from PCA and cracking model from AAHTO can be used on RCCP at certain design thickness range.
        3.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: A composite pavement utilizes both an asphalt surface and a concrete base. Typically, a concrete base layer provides structural capacity, while an asphalt surface layer provides smoothness and riding quality. This pavement type can be used in conjunction with rollercompacted concrete (RCC) pavement as a base layer due to its fast construction, economic efficiency, and structural performance. However, the service life and functionality of composite pavement may be reduced due to interfacial bond failure. Therefore, adequate interfacial bonding between the asphalt surface and the concrete base is essential to achieving monolithic behavior. The purpose of this study is to investigate the bond characteristics at the interface between asphalt (HMA; hot-mixed asphalt) and the RCC baseMETHODS: This study was performed to determine the optimal type and application rate of tack coat material for RCC-base composite pavement. In addition, the core size effect, temperature condition, and bonding failure shape were analyzed to investigate the bonding characteristics at the interface between the RCC base and HMA surface. To evaluate the bond strength, a pull-off test was performed using different diameters of specimens such as 50 mm and 100 mm. Tack coat materials such as RSC-4 and BD-Coat were applied in amounts of 0.3, 0.5, 0.7, 0.9, and 1.1ℓ/m2 to determine the optimal application rate. In order to evaluate the bond strength characteristics with temperature changes, a pull-off test was carried out at -15, 0, 20, and 40 °C. In addition, the bond failure shapes were analyzed using an image analysis program after the pull-off tests were completed.RESULTS: The test results indicated that the optimal application rate of RSC-4 and BD-Coat were 0.8ℓ/m2, 0.9 ℓ/m2, respectively. The core size effect was determined to be negligible because the bond strengths were similar in specimens with diameters of 50 mm and 100 mm. The bond strengths of RSC-4 and BD-Coat were found to decrease significantly when the temperature increased. As a result of the bonding failure shape in low-temperature conditions such as -15, 0, and 20 °C, it was found that most of the debonding occurred at the interface between the tack coat and RCC surface. On the other hand, the interface between the HMA and tack coat was weaker than that between the tack coat and RCC at a high temperature of 40 °C.CONCLUSIONS: This study suggested an optimal application rate of tack coat materials to apply to RCC-base composite pavement. The bond strengths at high temperatures were significantly lower than the required bond (tensile) strength of 0.4 MPa. It was known that the temperature was a critical factor affecting the bond strength at the interface of the RCC-base composite pavement.
        4,000원
        4.
        2017.05 구독 인증기관·개인회원 무료
        The mesenchymal stem cells (MSC) has been investigated as a source of stem cell therapy to replace and treat damaged cells. Human endometrial epithelial and stromal cells was isolated from hysterectomy tissue and the direct evidence of stem/progenitor cells in the human endometrium was identified. Endometrium derived stem cells (EnMSCs) are known to have a high proliferative ability, genetic stability, lack of tumorigenicity and low immnunogenicity during long-term cultivation. Here, we aimed to identify MSC in canine endometrium and characterize its potential to differentiate into decidua cells. EnMSCs were isolated from thrown-away spayed uterus of adult canine depending on their estrus cycle, and identified by flow cytometry, immunocytochemistry and flow cytometry with MSC specific markers. We then characterized the ability of EnMSCs by the doubling-time analysis, colony-forming units and MSC differentiation assays. Isolated EnMSCs expressed stem cell specific genes (Sox2, Oct4, Nanog, MCAM, Endoglin, Susd2 and IGTB) and MSC surface markers (CD90, CD44 and CD117). EnMSCs are also differentiated into adipogenic, osteogenic and chondrogenic cells morphologically under modified conditions with the expression of lineage specific genetic markers. EnMSCs showed higher proliferation ability than canine amniotic fluid derived MSCs which were used as a positive control. EnMSCs were cultured at low density (10, 20, cells/cm2) and initiated to form small colonies of loosely-arranged cells and gradually formed large colonies of densely-packed cells which underwent self-renewal with high proliferative potential which is similar to the clonogenicity feature of human endometrium-derived stem cells. EnMSCs were then induced to differentiate into decidua cells with 0.5 mM dbcAMP. After 14 days, EnMSCs changed their morphology into the elongated and rounded shape. The induced decidual cells expressed PRL and IGFBP1 which are typically expressed in decidua cells. In conclusion, we successfully isolated and characterized MSC in the canine endometrium which differentiated into decidua cells. These results showed that endometrium may be a promising source of stem cells, and furthermore raise the possibility of canine EnMSCs as a novel hypothetical decidualisation model of infertility associated with decidualisation insufficiency and implantation failure.
        5.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to compare and analyze the difference of the ankle joint movements during landing. Seven adult males voluntarily participated in the study and the average foot size of the subjects was 269.8 mm. Image analysis equipment and the ground reaction force plate (landing type) was used to measure th kinetic variables. As a result of this study, it was confirmed that the vertical ground reaction force peak point appeared once in the barefoot with forefoot, while two peak points appeared in the barefoot and functional shoe foot with rear foot landing. About ankle angle, fore foot landing ankle angle, the average with bare foot landing was -10.302° and the average with functional shoe foot landing was -2.919°. Also about rear foot landing, ankle angle was 11.648° with bare foot landing and 15.994° with functional shoe landing. The fore foot landing, ankle joint force analysis produced 1423.966N with barefoot and 1493.264N with functional shoes. But, the rear foot landing, ankle joint force analysis produced 1680.154N with barefoot and 1657.286N with functional shoes. This study suggest that the angle of ankle depends on the landing type and bare foot running/functionalized shod running, and ankle joint forces also depends on landing type.
        4,000원
        6.
        2016.10 구독 인증기관·개인회원 무료
        Somatic cell nuclear transfer (SCNT) has been considered for preserving genetically valuable or endangered animals. Sapsaree is a Natianal Monument in Korea to maintian a pure pedigree. The aim of this study was to produce azoospermia Sapsaree using SCNT and identify normal reproductive ability of cloned azoospermia Sapsaree. Ear skin biopsy was performed on a thirteen-year-old azoospermia Sapsaree and ear skin fibroblasts were isolated for SCNT as donor cells. The fibroblasts were injected into enucleated in vivo matured oocytes, the couplets were electrical fused by two pulse of direct current (55 V for 15 μs) using titanium and platinum fusion needle and activated by calcium ionophore. Cloned embryos were surgically transferred into oviducts of natuarally estrus cycle synchronized recipient dogs. The fusion rate of platinum needle was 70%, which was higher than those of titanium needle (64.1%). Developmental rate to the 8 cells and 10 cell stages was higher in platinum needle group (24% and 16%, respectively) than those of platinum needle group (14.8% and 3.1%, respectively). Total 35 SCNT embryos were transferred into oviducts of 3 recipient dogs and one recipient finally delivered a puppy by caesarean section. As results, this study demonstrated that platinum fusion needle could be successfully make the reconstructed embryos and improve the efficiency of canine SCNT. Cloning azoospermia Sapsaree may contribute to conserve genetically valuable and unique pedigree. And further study should be confirm whether cloned live dog is azoospermia.
        7.
        2016.10 구독 인증기관·개인회원 무료
        The cancer and Parkinson's disease associated protein DJ-1 is multifunctional protein that involves in diverse cellular process. DJ-1 protein has a cellular protective role and promoted cell survival under an oxidative stress. However, the cellular protective mechanism of DJ-1 is not fully understand, and we needs to be further study their functions in novel organisms. In the present study, we investigated the protective role of DJ-1 against induced oxidative stress in canine cell line. On the basis of these experiments, canine DJ-1 overexpressing and null cell lines were established. The stable overexpression and down regulation of DJ-1 efficiency confirmed by the western blot analysis. Subsequently, the DJ-1 gene transfected cell lines and control cells were subjected to induced the oxidative stress, and then cell viability, cell proliferation assay, cellular apoptosis detection analysis (Annexin V and TUNEL assay), intracellular ROS and mitochondrial activity were measured appropriately. The results showed that DJ-1 overexpressed cells were up-regulated cell viability under oxidative stress conditions induced by the rotenone and hydrogen peroxide (H2O2), whereas loss of DJ-1 cells were down-regulated the cell survival activity. Additionally, overexpression of DJ-1 cells increased cell resistance to oxidative stress and inhibited the elevation of cell death and cellular ROS induced apoptosis. Moreover, DJ-1 overexpressed cells was increased mitochondrial functions by using confocal microscopy with MitoTracker staining. On the contrary to this, DJ-1 null cells show defective cellular protection and mitochondria activity against oxidative stress conditions. Our data indicate that canine DJ-1 protein attenuates cellular apoptosis and ROS generation, enhances the cellular survival activity and promote mitochondrial function under the oxidative stress, likewise other mammalian cells. Importantly, DJ-1 overexpression may be an important part of a protective strategy as a sensor for oxidative stress.
        8.
        2016.06 구독 인증기관·개인회원 무료
        To obtain information on the sanitary of indoor environment in greenhouses used for shiitake cultivation, bacteria associated with larvae and imagoes of Sciaridae flies, pest to shiitake mushroom, were isolated and identified. A total of 1,048 bacterial colonies were isolated from the flies’ larvae and 984 bacterial colonies were isolated from the flies’ imagoes. Based on molecular analysis of the 16S rDNA sequence, Achromobacter xylosoxidans and Tetrathiobacter kashmirensis of β-proteobacteria, Enterobacter asburiae and Raoultella ornithinolytica of γ -proteobacteria, Curtobacterium sp. and Microbacterium thalassium of Actinobacteria, and Penibacillus taichungensis of Firmicutes were identified from the colonies of the flies’ larvae. While, Bacillus megaterium, B. thuringiensis, Lysinbacillus sphaericus and L. fusifomis of Firmicutes, Microbacterium thalassium and Citricoccus parietis of Actinobacteria, and Enterobacter asburiae of γ-proteobacteria were identified from the flies’ imagoes. Some of the isolated bacterial species were known be human pathogens. Overall, the results of this study suggested that mushroom fly carrying human pathogenic bacteria is one of sources impact on the sanitary of indoor environment of greenhouses used for shiitake cultivation.
        9.
        2015.10 구독 인증기관·개인회원 무료
        In the present study, Cydia kamijoi Oku is newly recognized in korean insect fauna. This tortricid moth was first found damaging the cones of Abies koreana in Jeju Island 2014. The moth can be a serious insect pest on A. koreana because of high damage rate on the cones, up to 71% average. The genus Cydia now was 11 korean species including C. kamijoi. Regarding this species, some basic information such as collection records, morphological characters, and ecology were provided
        10.
        2014.04 구독 인증기관·개인회원 무료
        A long term monitoring was carried out to compare altitudinal effects on insect community structures on high mountains and evaluate responses the monitoring and changed of insect communities induced by the climate change. These mountains were choose for Mt. Jeombong for northern part, Mt. Ilwol for middle and Mt. Beakun for southern. Each mountain was divided into three altitudinal gradients. They were collected three times a season from spring to autumn, using pitfall traps for ground beetles and UV light trap for moths. The present study presents preliminary results of analysis for the first year monitoring. In total 41beetle species and 326 moths were collected from the monitoring sites in 2012. abundance of ground beetles and moths were the highest in Mt. Baekun followed by Mt. Ilwol and lowest in Mt. Jeombong. Analysis of variance (ANOVA) results showed statistically significant differences among sampling area, species evenness and Shannon’s diversity index with altitude in species abundance as a response variable. Also we found statistically significant differences to three species of ground beetle and six species of moths with altitude. Although we expected a distinct cluster with the difference of altitude at each study site. one of ordination analysis, nonmetric multidimensional scaling (NMS), showed distinct clusters with the ground beetles assemblage at some altitude and moths assemblage at sampling date.
        14.
        2012.06 구독 인증기관·개인회원 무료
        True hermaphrodites are animals of equivocal sex in which both male and female gonads develop simultaneously. The frequency of true hermaphroditism is higher in pigs than in other domestic animals. Two Korean pigs were diagnosed with true hermaphroditism showing ovotestes, epididymes, penes, and uteri. Histomorphologically, the testicular tissues consisted of Sertoli cells that were devoid of spermatogenic germ cells and showed proliferation of interstitial cells. However, the uteri were of normal architecture and had well-developed uterine endometrial glands. The samples were 38, XX female karyotype without the sex-determining region Y (SRY) gene. The findings of this study could contribute to the understanding of true hermaphroditism in the Korean pig industry. * This work was supported by a grant (Code# PJ008148) from BioGreen21 Program, Rural Development Administration, Republic of Korea.
        15.
        2012.06 구독 인증기관·개인회원 무료
        The aim of this study was to examine the effect of acteoside (the cyclin-dependent kinase inhibitor) on the SCNT efficiency with adult fibroblasts in dog. Canine adult fibroblasts were obtained from muscle and cell cycle of fibroblasts was synchronized by culturing to confluency, serum starvation and treating with 30 μM acteoside for 48 h. Cell cycle stages, cell cytotoxicity (apoptosis) and, prduction of reactive oxygen species (ROS) were analyzed using flow cytometry. The canine cells, prepared by confluent-cell culture or treating with 30 μM acteoside for 48 h, were injected into enucleated in vivo matured oocytes, the couplets were electrical fused and activated by calcium ionomycin. SCNT embryos using acteoside-treated fibroblasts were surgically transferred into oviducts of estrus cycle synchronized recipient dogs. In cell cycle synchronization (G0/G1), there was no significant difference between serum starvations (83.9%) and acteoside treated groups (81.3%) that were higher than confluent group (78.5%). In production of apoptosis, confluent and acteoside treated groups (4.3 and 4.5%, respectively) were generated less than serum starvation group (21.8%). In case of ROS, serum starvation group was induced a significantly higher than other groups. After synchronization of the donor cell cycle, either confluent or acteoside treated, cells were placed with enucleated in vivo-matured dog oocytes, fused by electric stimulation, activated, and transferred into naturally estrus-synchronized surrogates. Fusion and cleavage rate of acteoside treated group were 64.1 and 41.5%, which were higher than those of confluent group (53.9 and 20.6%, respectively). The reconstructed embryo development rates to 4-cell and 8-cell in acteoside treated group were 29.5 and 14.8%, respectively, while confluent group showed 11.1 and 3.2%, respectively. Total 54 SCNT embryos using acteoside-treated fibroblasts were transferred into oviducts of 2 recipient dogs and one recipient finally delivered one puppy, whereas din`t detected pregnancy on transfer of cloned embryos reconstructed with confluent cells in 6 surrogate dogs. In conclusion, the results of the current study demonstrated that canine fibroblasts could be successfully arrested at the G0/G1 stage with reduced the formation of ROS and apoptosis after acteoside treatment. This results may contribute to improve the effi-ciency of canine SCNT. * This research was supported by iPET (Grants 110056-3), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
        16.
        2012.06 구독 인증기관·개인회원 무료
        Acteoside acts as an anti-oxidative activity and anti-apoptosis in the cells. But, it has been not studied on maturation and development of porcine oocytes. The aims of the present study were to examine the effects of acteoside on the morphological progress of meiosis, developmental competence, and ROS in porcine oocytes. Oocytes were matured in tissue culture medium-199, supplemented with acteoside at various concentrations: 0 (control), 10, 30 and 50 μM. The oocytes maturation rates of groups supplemented with acteoside were no significantly different (81.13, 85.96, 82.95 and 83.68%, 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 (44.83 vs. 27.75%). 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. In the results. during IVM, 10 μM acteoside treated oocytes showed that the mitochondria and lipid droplet were smaller and homogeneous distribution in cytoplasm compare with control oocytes. And reverse transcription polymerase chain reaction (RTPCR) of parthenogenetic blstocysts revealed that acteoside increased the anti-apoptotic genes (Mcl-1, Bcl-2 and Bcl-xL), whereas reduced the expression of pro-apoptotic genes (Bax and Bak). In conclusion, based on the results, the effect of acteoside on IVM was not attractive. However, in acteoside treated group, cytoplasmic maturation seemed to be improved with morphologically uniform distribution of cytoplasmic organelles. Furthermore, embryonic development in acteoside treated group was significantly highly increased than that of non-treated group. Our results represents that addition of acteoside to the IVM medium has a beneficial effect in physiology of porcine oocytes, providing a improved method for porcine oocytes in vitro. * This work was supported by a grant (Code# PJ008148) from BioGreen21 Program, Rural Development Administration, Republic of Korea.
        17.
        2012.06 구독 인증기관·개인회원 무료
        The objective of the current study was to describe in vitro embryo production in Hanwoo, analyzing oocytes yield and embryo production. The effects of oocytes production and the number of OPU procedures per animal on embryo production were also evaluated. OPU was done every 3~4 days during experimental period and collected oocytes were fertilized in vitro in both OPU and needle puncture groups. First, we compared the recovery rate of oocytes based on OPU session (Experiment 1). The average of collected oocytes was calculated from every 10 session. The average number of total oocytes recovered per animalonsessionwas 5.16 (mean). Second, we compared the recovery rate base on collection period of OPU (Experiment 2). The following results show the difference of the number of recovered oocytes in every month during the procedure between the months of session. Every animal shows the constant number of recovered oocytes for the first 5 months. However, the recovery rate of oocytes was decreased from month 6 to 8. Third, we compared the developmental rate to blastocyst in two groups (Experiment 3). Oocytes by needle puncture were fertilized with frozen-thawing semen; the cleavage rate 24~48 h after in vitro fertilization (IVF) was 75.8% and blastocyst development rate was 18.8% in needle puncture group. Even though there is lower cleavage rate after IVF in OPU group (61.1%), blastocyst development rate was higher compared with needle puncture group (28.4%). In conclusion, Blastocyst developmental rate could be increased by OPU than classical method of needle puncture. Improvement of bio- technique in collecting oocytes could be applied to understand the reproductive physiology in cattle, expecially Hanwoo. Therefore, further investigation should be done to clarify the efficiency and advantage of OPU involved in reproduction in animals and human being.
        18.
        2011.10 구독 인증기관·개인회원 무료
        The objective of this study was to evaluate in vitro production of bovine embryos in Hanwoo. Oocytes were collected by ovum pick up (OPU) from ovaries of genetically high-value Hanwoo or by needle puncture from ovaries of slaughtered cattle. OPU was done every 3 4 days duing experimental period and collected oocytes were fertilized in vitro in both OPU and needle puncture groups. First, We compared the in vitro maturation rate in two groups (Experiment 1). 545 oocytes were recoverd from 4 females by 32 trials of OPU and then 433 oocytes were shown MⅡ stage after in vitro maturation (79.4%). In case of needle puncture group, 1905 oocytes were collected and then 1420 oocytes were matured to MⅡ stage during in vitro culture(74.5%). Second, we compared the developmental rate to blastocyst in two groups (Experiment 2). 1420 oocyte by needle puncture were fertilized with frozen-thawing semen; the cleavage rate 24 48 h after in vitro fertilization (IVF) was 88.6% and blastocyst development rate was 20.5% in needle puncture group. Even though there is lower cleavage rate after IVF in OPU group (84.8%), blastocyst development rate was higher compared with needle puncture group (26.4%). In conclusion, Blastocyst developmental rate could be increased by OPU than classical method of needle puncture. Improvement of bio-technique in collecting oocytes could be applied to understand the reproductive physiology in cattle, expecially Hanwoo. Therefore, further investigation should be done to clarify the efficiency and advantage of OPU involved in reproduction in animals and human being. This research was suppoted by Imsil-gun agricultural technology service center.
        19.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze and compare the effect of resistance exercise and balance exercise on proprioception and WOMAC index of patients with degenerative knee osteoarthritis. A total of 40 subjects participated in this study. The subjects were diagnosed with degenerative knee osteoarthritis and all were more than 60 years old. They were divided into three groups. Group Ⅰ(n=8) was trained with resistance exercise, Group Ⅱ(n=6) was trained with balance exercise and GroupⅢ(n=6) was trained with range of motion as a control. The results of this study were as follows. It was significantly indicated that the resistance exercise group and balance exercise group elicited error-reduction on proprioception goal-angle (p<.05). There was a statistically significant difference on proprioception between resistance exercise group and control(range of motion) group. There was a statistically significant reduction on WOMAC index between resistance exercise group and balance exercise group (p<.05) and on the WOMAC index between resistance exercise group and range of motion group(p<.05). In conclusion, resistance exercise and balance exercise are effective on degenerative knee osteoarthritis and resistance exercise is the most effective for improving proprioception and WOMAC index. More research on the intervention according to the degree of degenerative knee osteoarthritis is needed.
        4,000원
        20.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the difference of the pinch strength according to testing posture(standing and sitting) and elbow flexion degree(0。, 45。, 90。and 135。). Forty normal young adults(male: 20, female: 20, mean age: 22.68±2.91 years) participated in this study. The methods of this study were categorized as follows: 1) One set of measurement was performed on four elbow flexion degrees(0。, 45。, 90。and 135。) in two testing postures(standing and sitting) and all subjects were measured for 3 sets testing procedures in every experimental sessions. 2) Pinch strength in various elbow flexion degree was measured after 2 min rest time, and then each test set was repeatedly performed with 5 min rest time to prevent fatigue of muscles involved in the elbow joint. The result was obtained as follow: 1) In standing posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 2) In sitting posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 3) Statistically, there was no significant difference between standing and sitting posture in same elbow flexion degree, however pinch strength in standing posture was higher than sitting posture.
        4,000원
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