폭발 수치해석 기법 중 Arbitrary Lagrangian-Eulerian(ALE)는 구조물의 파괴뿐만 아니라 폭발 이후 충격파의 전파 과정까지 관찰할 수 있는 장점이 있다. 그러나 동적 해석 시 유한요소 모델의 격자망 크기가 일정 수준 이하로 감소하게 되면 해석 결과의 신뢰도가 부 정확해진다. 본 연구에서는 ALE 수치해석 기법을 활용하여 대기의 격자망 크기가 해석의 정확도에 미치는 영향을 조사한다. 다양한 조건의 격자망 크기와 폭발 중량을 갖는 대기 중 폭발모델을 구축하고, 폭발 중심으로부터 거리에 따른 폭발압력을 관찰한다. 수치해 석과 실험에서 얻은 최대 폭발압력 결과에 대해 평균 제곱 오차를 계산하여 최적의 격자망 크기를 제안하고, 제안된 크기를 바탕으로 폭발물 중량과 대기의 최적 격자망 크기에 대한 상관관계를 분석한다. 본 연구는 다양한 중량을 가진 폭발물 해석에서 최적의 격자망 크기를 제공함으로써 신뢰성이 향상된 폭발 수치해석 모델 개발에 도움이 될 것으로 기대한다.

우수한 역학적 성능을 가진 생물체의 구조를 모방하여 고성능의 복합재료를 개발하려는 노력이 최근 활발히 이뤄지고 있다. 진주 층 구조는 구성재료 대비 월등히 높은 파괴인성을 지닌다는 점에서 촉망받는 자연 모사 구조 중 하나이다. 하지만, 진주층 모사 구조의 형상이 변형될 때 구조의 충격성능이 어떻게 달라지는지에 관한 연구는 아직 충분히 진행되지 않았다. 본 연구에서는 무작위로 변형 된 진주층 모사 복합재의 수치모델을 개발하고 충격성능을 분석하였다. 먼저, 균일한 진주층 모사 패턴에서 플레이트 판의 평면 크기 를 무작위로 변형하는 알고리즘을 개발하고 이를 활용하여 불균일한 진주층 패턴 모사 구조를 모델링하였다. 그 후, 낙하충격 시뮬레 이션을 수행하고 해당 모델의 충격거동을 에너지 흡수율과 본 미세스 응력 분포, 충격력-시간 그래프를 활용하여 평가하였다. 수치해 석결과를 바탕으로, 충돌 범위 주변 플레이트 판의 기하학적 형상이 불균일할수록 진주층 모사 구조의 내충격성이 저하됨을 입증하 였다. 이러한 진주층 모사 형상에 대한 심층적인 이해는 진주층 모사 구조의 최적설계를 수립하는 데 효율적으로 활용될 수 있을 것으 로 기대된다.

배경/목적: 내시경역행담췌관조영술(endoscopic retrograde cholangiopancreatography, ERCP)은 췌장담도 질환의 진단 및 치료에 효과적인 시술법으로 알려져 있다. 한국에서는 40년 이상 ERCP 시술에 대한 범국가적 데이터가 축적되어 있으나 시술에 대한 경향과 특성에 정보는 미미하다. 본고는 ERCP 건수 및 현황에 대한 전국 데이터를 조사하였다. 방 법 : 2012년부터 2015년 사이에 ERCP와 관련된 국민건강보험심사평가원 청구 데이터를 분석하였다. ERCP 시술건수와 시술과 관련된 특성, 시술을 시행 받은 환자의 건수 및 인구역동학적 특징 등을 조사하였다. 결과: 조사에 해당하는 기간에 158,038건의 ERCP 시술이 114,757명의 환자에게 시행되었다. ERCP 전체 수는 매년 증가하였으며, 특히 치료 ERCP의 비율이 증가 추세를 보였다. 시술의 약 2/3 (63.3%)가 종합병원 이상의 규모 큰 기관에서 시행되었다. 2015년에는 시술은 받은 80세 이상의 고령 환자 비율이 2011년 14.3%에서 2015년은 17.2%로 증가하였다. 결론: 한국에서 매년 시행되는 ERCP의 시술 건수는 증가 추세에 있다. 특히 치료 목적 또는 고령 환자의 시술이 뚜렷한 증가 추세를 보여 시술과 관련된 환자의 안전에 더 많은 주의가 요구된다.

Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.

Entomopathogenic fungi have been used as important part of integrated pest management program to control aphid. In particular, Beauveria bassiana was distributed throughout the world including temperate and tropical area, various habitats from alpine soil, desert soil to running water and both insect and plant. Especially the fungus has also been isolated from the surface and the interior of plants and act as natural control agent. Viability of fungi on the plant surface may be influenced by temperature, humidity, sunlight and plant type as well as fungal isolate. Persistence of treated fungal control agent on phylloplane and control efficacy may differ from environmental conditions and isolates. In this study, we investigated the persistence of an B. bassiana which is developing as prototype wettable powder to control cotton aphid, and the residual efficacy of the prototype on cucumber under three different greenhouse conditions.

Cotton aphid, Aphis gossypii Gloever is one of the major pests on a wide range of economically important crops in the world. The sustained use of chemical insecticides to control the aphid has led to the emergence of resistant strains to numerous used insecticides. As an alternative strategy entomopathogenic fungi have been used as part of integrated pest management program to control aphid, especially insecticide-resistance population. In particular, Beauveria bassiana-based commercial bio-insecticide has been used to reduce the pest population under greenhouse conditions in various countries. In this study, we investigated the control efficacy of a prototype of commercial mycopesticide using an B. bassiana (wettable powder) against cotton aphid on potted cucumber plant in greenhouse conditions.

Entomopathogenic fungi are natural enemies of insect pests and contribute to the natural regulation of their host populations. These fungal group are often used as active ingredients for microbial insect pest control. In addition, the potential antimicrobial effect by entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have recently been reported against fungal plant pathogens. Dual microbial control effects with entomopathogenic fungi against both aphids and cucumber powdery mildew had reported in Canada. In our previous studies we conducted bioassay with entomopathogenic fungi to develop dual microbial control agent which can control both aphid and fungal plant disease. We selected an Beauveria bassiana isolate which has high dual control effects against both cotton aphid, Aphis gossypii and sclerotinia rot, Sclerotinia sclerotiorum. In this study, we have tested the dual control efficacy of the B. bassiana isolate against cotton aphid and sclerotinia rot on whole potted cucumber plants. We found that the B. bassiana isolate protected the plant from cotton aphid and sclerotinia rot under laboratory condition.

Despite many researches related with in-vitro culture of porcine spematogonial stem cells (SSCs), adherent culture system widely used has shown a limitation in the maintenance of porcine SSC self-renewal. Therefore, in order to overcome this obstacle, suspension culture, which is known to have numerous advantage over adherent culture, was applied to the culture of porcine SSCs. Porcine SSCs retrieved from neonatal testes were suspension-cultured for 5 days or 20 days, and characteristics of suspension-cultured porcine SSCs including proliferation, alkaline phosphatase (AP) activity, and self-renewal-specific gene expression were investigated and compared with those of adherent-cul-tured porcine SSCs. As the results, the suspension-cultured porcine SSCs showed entirely non-proliferative and significantly higher rate of AP-positive cells and expression of self-renewal-specific genes than the adherent-cultured porcine SSCs. In addition, long-term culture of porcine SSCs in suspension condition induced significant decrease in the yield of AP staining-positive cells on post-day 10 of culture. These results showed that suspension culture was inappropriate to culture porcine SSCs, because the culture of porcine SSCs in suspension condition didn’t stimulate proliferation and maintain AP activity of porcine SSCs, regardless of culture periods.

Beet armyworm, Spodoptera exigua are difficult to control using chemical insecticides because of the development of insecticide resistance. For eco-friendly beet armyworm managements, various control agents are required. Entomopathogenic fungus is one of promise control agents as an alternative to chemical control agent. We isolated entomopathogenic fungi from soil samples of suwon by insect-bait method using Galleria mellonella and conducted bioassay to larva of beet armyworm. As a result of bioassay isolate FG274, FG340, FG344 had high virulence as 100% against second instar larva of S. exigua. To identify the fungus isolates, their’s morphological characteristic was observed and ITS of 18srRNA was sequenced. ITS sequence of FT274, 340, 344 were highly matched (100%) to that of Beauveria bassiana, Paecilomyces fumosoroseus, Metarhizium anisopliae. To investigate the optimal concentration, three isolates were sprayed at three different concentration(1×106 ,107 and 108 conidia/㎖) in laboratory conditions. 나타내었다.

Suspension culture is a useful tool for culturing embryonic stem (ES) cells in large-scale, but the stability of pluripotency and karyotype has to be maintained in vitro for clinical application. Therefore, we investigated whether the chromosomal abnormality of ES cells was induced in suspension culture or not. The ES cells were cultured in suspension as a form of aggregate with or without mouse embryonic fibroblasts (MEFs), and 0 or 1,000 U/ml leukemia inhibitory factor (LIF) was treated to suspended ES cells. After culturing ES cells in suspension, their karyotype, DNA content, and properties of pluripotency and differentiation were evaluated. As a result, the formation of tetraploid ES cell population was significantly increased in suspension culture in which ES cells were co-cultured with both MEFs and LIF. Tetraploid ES cell population was also generated when ES cells were cultured alone in suspension regardless of the existence of LIF. On the other hand, the formation of tetraploid ES cell population was not detected in LIF-free condition, in which MEFs were included. The origin of tetraploid ES cell population was turned out to be E14 ES cells and not MEFs by microsatellite analysis and the basic properties of them were still maintained despite ploidy-conversion to tetraploidy. Furthermore, we identified the ploidy shift from tetraploidy to near-triploidy as tetraploid ES cells were differentiated spontaneously. From these results, we demonstrated that suspension culture system could induce ploidy-conversion generating tetraploid ES cell population. Moreover, optimization of suspension culture system may make possible mass-production of ES cells.

The purpose of this study was to determine the effects of heat appli˗ cation on the immune activities of the human body. To exam, further˗ more, the immune effect from the healthy volunteer(male:15, female:15) by monitoring changes of immune substances such as various leukocytes[total white blood cell(WBC), eosinophil, neutrophil, basophil, monocyte, and lymphocyte], a comparative study with warm water immersion(40.8±0.3℃) and infrared(250W) was carried out. The plasma analysis showed that the count of white blood cell, eosinophil, and neutrophil were elevated in warm water immersion- or infrared˗ stimulated group compared with control group. However, the count of basophil was decreased in both warm water immersion- and infrared-stimulated group than control group. Therefore, these results suggest that the thermostimulation improved immune activity.

In this study, genetic diversity of wild Codonopsis lanceolata collected in Korea were analysed using SSR makers. Wild C. lanceolata roots were collected in Jeollanam-do Jangheung-gun Choentae Mountain as in roots. The wild C. lanceolata plants were cultivated in Chungbuk National University greenhouse and the leaves were sampled from 36 plants. The genomic DNA of C. lanceolata was extracted using CTAB. PCR was performed using a program of 35 cycles at 94℃ for 30 sec, 60℃ for 30 sec, and 72℃ for 30 sec with an pre-denaturation of 94℃ for 5 min and a final extension of 72℃ for 30 min. The PCR reaction mixture contains 5 pmole of primers and 20 ng of DNA template in a 20 μL reaction volume. The genotype of the analyzed samples were very different. Therefore, the wild C. lanceolata collected in Korea look genetically diverse.

Codonopsis lanceolata is a perennial climber. The roots are used as medicinal materials or vegetables. Recently, demand for C. lanceolata is increasing as a healthy food. C. lanceolata is distributed in India and East Asia such as China, Japan as well as Korea. In South Korea, this plant is widely cultivated in Gangwon-do province. No C. lanceolata varieties were developed in Korea. The objective of this study is to analyze genetic diversity of C. lanceolata cultivated in Korea using SSR makers. C. lanceolata roots were collected in each region were cultivated in Chungbuk National University greenhouse. Samples were obtained from fresh leaves of 5 plants from each collection region. The genomic DNA was extracted using CTAB. Genetic diversity was analysed using 4 sets of C. lanceolata SSR makers. PCR was performed in total 20 μL reaction volume containing 20 ng of DNA template, 5 pmole of primers. The genotypes of the analyzed samples were very similar. That means that the genetic diversity of C. lanceolata cultivated in Korea is very low.

Orchardgrass (Dactylis glomerata L.) is a Gramineae perennial grass species and commonly used as a forage crop and developed to be used for pasture. In Korea, in order to improve high persistence and forage quality, through selection of various superior parental varieties for breeding and synthesis of them with new lines, there are ongoing worldwide studies aiming to enhance the quality and environmental adaptability of Orchardgrass. Between 2010 and 2014, a Orchardgrass variety named Onnuri 2ho was developed by the Grassland & Forages Division, National Institute of Animal Science, Rural Development Administration (RDA), Republic of Korea. For the production of synthetic seeds for Onnuri 2ho 4 superior clones, Dg7506, Dg9508, Edg215 and Edg218 were selected and polycrossed. Between 2010 and 2011, the agronomic growth characteristics and forage production capability of the seeds were studied at Cheonan, and between 2012 and 2014, regional trials were conducted in Cheonan, Hoengseong, Jinju, and in Jeju. The main growth characteristic of Onnuri 2ho is a tetraploid variety, a medium-late maturity variety, the heading stage of which is around May 17, which is four days later than that of Amba. This study tested the regional adaptability of Orchardgrass in Cheonan, Hoengseong, Jeju, and in Jinju. The average dry matter yield of Onnuri 2ho in the four regions was 15,814 kg/ha, which is greater than that of Amba by 34%. These differences show that Onnuri 2ho is more resistant to environmental stresses than Amba and that this growth characteristic directly led to dry matter yield. Thus, Onnuri 2ho is a suitable variety for the establishment of grasslands as it has enhanced disease resistance and persistence, compared to Amba. The forage quality of Onnuri 2ho was similar to that of Amba in crude protein (11.5%), total digestible nutrients (59.2%), neutral detergent fiber (62.7%), and acid detergent fiber (37.6%), whereas the forage quality of Ongreen was higher than that of Amba in (71.0%). The new variety was selected and named Onnuri 2ho from Composite 34 by the RDA in November 2014, and the application for the protection of the new variety by the Korea Seed and Variety Service is currently pending. In this study, a new variety of Orchardgrass with excellent environmental adaptability was developed, in order to contribute to the vitalization of the Korean grassland industry.

A new standard rose cultivar 'White Christmas' was bred from the cross between red standard cultivar 'Red Queen' and pink standard cultivar 'Vivaldi' at the National Horticulture Research Institute. The cross was made in 2001 and `White Christmas' was finally selected in 2006 after investigating characteristics for three years from 2003 to 2006. 'White Christmas', a white standard cultivar grows vigorously and has good flower shape. The major characteristics of this cultivar are 123.8 stems/m2/year in yield, 82.3 cm in length of cut flower, 11.0 cm in flower diameter, 60.1 in petal number, and 12.2 days in vase life. This cultivar can be propagated by both cutting and grafting. The consumer's preference of this cultivar is relatively higher than that of control cultivar, 'Tineke'.