Comparison of trophic factors changes in the hippocampal CA1 region between the young and adult gerbil induced by transient cerebral ischemia.

Yan, Bing Chun,Park, Joon Ha,Kim, Sung Koo,Choi, Jung Hoon,Lee, Choong Hyun,Yoo, Ki-Yeon,Kwon, Young-Geun,Kim, Young-Myeong,Kim, Jong-Dai,Won, Moo-Ho Kluwer Academic/Plenum Publishers 2012 Cellular and molecular neurobiology Vol.32 No.8

<P>In the present study, we investigated neuronal death/damage in the gerbil hippocampal CA1 region (CA1) and compared changes in some trophic factors, such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF), in the CA1 between the adult and young gerbils after 5 min of transient cerebral ischemia. Most of pyramidal neurons (89%) were damaged 4 days after ischemia-reperfusion (I-R) in the adult; however, in the young, about 59% of pyramidal neurons were damaged 7 days after I-R. The immunoreactivity and levels of BDNF and VEGF, not GDNF, in the CA1 of the normal young were lower than those in the normal adult. Four days after I-R in the adult group, the immunoreactivity and levels of BDNF and VEGF were distinctively decreased, and the immunoreactivity and level of GDNF were increased. However, in the young group, all of their immunoreactivities and levels were much higher than those in the normal young group. From 7 days after I-R, all the immunoreactivities and levels were apparently decreased compared to those of the normal adult and young. In brief, we confirmed our recent finding: more delayed and less neuronal death occurred in the young following I-R, and we newly found that the immunoreactivities of trophic factors, such as BDNF, GDNF, and VEGF, in the stratum pyramidale of the CA1 in the young gerbil were much higher than those in the adult gerbil 4 days after transient cerebral ischemia.</P>

북한 김정은 정권의 국가목표와 군사정책 방향: 새로운 위협 요소의 등장과 한국의 대응전

이영종(Lee, Young-jong) 한국전략문제연구소 2020 전략연구 Vol.27 No.1

지난 2018년 초 대남 유화국면으로 급전환하며 대미협상을 주축으로 한 새로운 생존 전술을 구사하는 모습을 연출한 김정은 북한 국무위원장은 약 2년 만인 2019년 말 노동당 중앙위원회 제7기 5차 전원회의 개최를 계기로 다시 강경 노선 쪽으로 선회하며 “조·미 간의 교착 상태는 불가피하게 장기성을 띠게 되어있다”고 선언했다. 세계적 대유행 양상을 빚고 있는 신종 코로나바이러스(코로나19)는 대북 문제에 대한 관련국들의 집중력을 떨어트리고 있으며, 북한 또한 ‘셀프제재’로까지 불리는 사실상의 교류·교역 전면차단 조치를 취하면서 방역에 전력투구하고 있다. 이런 상황 속에서 북한이 향후 어떤 전술이나 전략을 앞세워 대남, 대미 정책을 펼쳐나갈지는 한반도와 주변 정세에 결정적 영향을 미칠 수 있는 변수가 될 수 있다. 하지만 2012년 김정은 체제 등장 이후에 북한의 핵 실험과 장거리 미사일 도발이 이어졌음에도 불구하고 이에 대한 면밀한 연구나 대응책 마련이 북한의 국가목표나 군사정책 차원에서 깊이 있게 다뤄지지 못한 측면이 있다. 김정은 집권 이후 통치노선이나 스타일에서 드러난 두드러진 특징 가운데 하나는 ‘국가’로서의 북한체제를 공식화하고 부각시키고 있다는 점이다. 김정은 스스로 ‘국무위원회 위원장’이란 직함을 사용하고, ‘조선인민군 최고사령관’이란 호칭 대신 ‘조선민주주의인민공화국 무력 최고사령관’으로 칭해지고 있는 점에서도 이를 확인할 수 있다. 김정은 체제는 대남 및 대미 외교와 경제·사회 등의 분야에서 이전과 다른 전향적 조치들을 취함으로써 변화와 개혁·개방에 대한 기대를 불러일으키기도 했으나 △당 국가 체제의 유지 △핵보유국 지위 굳히기 △경제·핵 병진 노선과 그 변용 △대미접근과 미국에 대한 이중적 인식 등에서 북한 체제의 국가목표 근간이 그대로 유지·고수되고 있음을 드러내고 있다고 볼 수 있다. 김정은 정권의 중요한 국가 목표 중 하나는 핵과 미사일의 완성을 기반으로 하는 한반도 적화통일이며, 군사정책도 이런 대목에 초점이 맞춰진 것이다. 북한의 이런 국가목표나 군사정책에 대한 우리의 정책적 대응은 △북핵 불용에 대한 공감대 형성과 대북압박 △사실상의 ‘핵보유국’ 북한에 대한 현실적 대응 △개혁ㆍ개방 및 국제무대 유인 등이 고려될 수 있다. North Korea"s policy in the midst of rapid changes in the situation on the Korean Peninsula can have a major impact on inter-Korean relations and surrounding circumstances. The need for closer analysis on North Korea"s military policy directions, the nature of its national strategy as well as its nuclear weapon and missile has grown. The purpose of this article is to analyze the ultimate national goal and military policy direction pursued by the Kim Jong-un regime and to diagnose Korea"s counterstrategy. One of the prominent features of Kim Jong-un"s policy line after his inauguration was his emphasis on the North Korean regime as a “state”. The Kim Jong-un regime"s national goals and visions were presented concretely at the Labor Party"s 7th Labor Party Congress held in May 2016, setting a five-year strategic period for national economic development (2016-2020) and building a socialist economic power as a banner. Yet, more national goals and visions still remain undisclosed, considering most of them are often secretly established and promoted. North Korea"s appeasement toward South Korea and the United States since 2018 has changed the impression of the Kim Jong-un regime from an aggressive, provocative regime to open, reconciling and cooperation-oriented regime. However, North Korea showed no more than superficial and tactical gestures, failing to take fundamental actions like denuclearization. As military policy line of Kim Jong-un regime backed by nuclear missile weapon gets more sophisticated and belligerent, importance of South Korea"s countermeasures have grown. Strategic counteractions based on military power should be taken against North Korea’s two-sided strategy such as nuclear and missile provocations and unification frontline tactics. Furthermore, counter strategies that can closely analyze and cope with the United States and China’s policies refer to Korean Peninsula are nessesary.

Hepatic Cirrhosis Occurring in a Young Woodchuck(Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus(WHV)

Kyu-shik Jeong,정원일,Jae-yong Chung,Mi-young An,Chae-yong Jung,Gyoung-jae Lee,Jong-soo Kang,Byeong-cheol Kang,Young-heun Jee,Bruce H Williams,Young-oh Kwon,Da-hee Jeong 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Cirrhosis Occurring in a Young Woodchuck (Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus (WHV)Da-hee Jeong, Won-il Jeong, Jae-yong Chung, Mi-young An, Chae-yong Jung, Gyoung-jae Lee1, Jong-soo Kang1, Byeong-cheol Kang2, Young-heun Jee3, Bruce H Williams4, Young-oh Kwon5 and Kyu-shik Jeong*College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea1Shinwon Scientific Co., LTD, Research Institute, Suwon, Korea2Clinical Research Institute, Seoul National University, Seoul 110-744, Korea3College of Veterinary Medicine, Jeju National University, Jeju 690-756, Korea

40세 이하 관상동맥 질환자에서 장기적 임상 관찰

이승욱,정명호,박종철,박형욱,조상희,김원,김계훈,이상현,강경태,조장현,김남호,김건형,안영근,조정관,박종춘,강정채 全南大醫大 2001 전남의대학술지 Vol.37 No.2

Preparation of petroleum impregnating pitches from pyrolysis fuel oil using two‑step heat treatments

Jong‑Eun Choi,Seunghyun Ko,Young‑Pyo Jeon 한국탄소학회 2019 Carbon Letters Vol.29 No.4

Petroleum-based impregnating pitches were prepared from pyrolysis fuel oil (PFO) using a two-step heat treatment without a separation process. The pressurized heat treatment, the first step, was used to improve the properties of the pitches and enhance the product yield by promoting the cracking and polymerization of the components in the PFO. An atmospheric heat treatment as the second step was used only to synthesize the impregnating pitches from the liquid pitches prepared during the first step. The prepared impregnating pitches had the properties of a commercial petroleum-based impregnating pitch. The impregnation performance was evaluated by HT-XRD and an impregnation test. The HT-XRD results showed changes in the stacked structure of the pitches at the impregnation temperature. The bulk density of the carbon block was increased to 14.3% and the porosity was reduced by 10.3% after the impregnation/recarbonization process. The high reaction temperature during the first step induced the formation of quinoline insoluble (QI) components during the second step of the treatment, and the QI components adversely affected the impregnation process.

Effects of Humidity on the Microstructure and the Ferroelectric Properties of Sol-Gel grown P(VDF-TrFE) Films

Young Joon Ko,진다운,Dae Sol Kong,Jong Hoon Jung 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.4

We report the microstructure and the ferroelectric properties of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] films grown under various humidity conditions and synthesis times by using a sol-gel method. When the synthesis time under a humid condition was short (approximately 30 min), the moisture in the environment affected only the surface morphology without any loss of ferroelectricity for the P(VDF-TrFE) films. In contrast, when the synthesis time was long (approximately 90 min), the moisture strongly affected the microstructure and the ferroelectric properties of P(VDF-TrFE). The transparent P(VDF-TrFE) film became opaque at high humidity. Scanning electron microscopy revealed numerous pores on the surface of and inside the film. The pores reduced the Young's modulus considerably from 4.15 to 0.97 GPa for the films grown at 20 and 80% relative humidity, respectively. In addition, the ferroelectric hysteresis loop disappeared at humidities above 60%. This work provides upper limits for the humidity and the synthesis time for the growth of high-quality P(VDF-TrFE) films by using a sol-gel method.

Interface Shear Strength at Joints of Ultra‑High Performance Concrete Structures

Young?Jin Kim,Won?Jong Chin,Se?Jin Jeon 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.6

When ultra-high performance concrete (UHPC) is fabricated as precast members such as in a UHPC segmental bridge, the joint design between the precast members can significantly affect the overall integrity and safety of the structure. Therefore, the structural behavior of the UHPC joint was experimentally investigated in this study with test variables including joint type, number and height of shear keys, type of filler, curing temperature, and lateral compressive stress. The UHPC considered in this study is the K-UHPC developed in Korea with a specified compressive strength as high as 180 MPa and high flowability. The joint shear strengths affected by the test variables were investigated in detail. The test results were also compared with two representative predictive equations for interface shear strength to determine an appropriate equation for the joint design of UHPC. These equations did not match well with the test data because they were originally proposed for normal strength concrete. However, the JSCE equation could be improved by modifying a coefficient to show good agreement with the test especially in the case of the dry joint with epoxy application.

Vertical pattern of interconnects to bypass high strain near a hard die on a flexible substrate under mechanical bending

Jong-Sung Lee,Young-Joo Lee,Jaegeun Seol,Young-Chang Joo,Byoung-Joon Kim 대한금속·재료학회 2024 ELECTRONIC MATERIALS LETTERS Vol.20 No.2

The distinguishing feature of a fl exible electronic device is that it maintains its function even when the shape changes repeatedly. As the degree of integration of fl exible devices increases, revealing failure mechanisms and extending the lifetime ofthe fl exible devices are getting more diffi cult. One of the potential damage zones is the interface of heterogeneous materialcomponents, where strain can be localized due to the mismatch of mechanical properties. In this study, we investigate themechanically reliable interconnect design of the fl exible printed circuit board (FPCB) system in which the packaging chipis integrated. When the FPCB was bent, folding occurred at the edge of the packaging chip due to the high bending rigiditycompared with the plastic substrate and resulted in high strain concentration. By introducing interconnect architecture thatbypassed the strain concentration area around the packaging chip, mechanical damage of the interconnects was successfullyreduced. Through fi nite element simulation, the strain applied to the interconnect crossing the strain-concentrated regionwas predicted to be 2 times larger than that bypassing the strain-concentrated region, from 8.32 to 4.64%. In addition, thestrain gap of these two interconnects could be increased as the Young’s modulus mismatch between the packaging chip andthe substrate increased. This study is expected to improve the design guidelines to mechanically reliable interconnects inhighly integrated fl exible electronics.

단일 단계 접착제의 변연 미세누출

조영곤,정진호,기영재,최희영,진철희,유상훈,김종욱,박병철 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.2

This study evaluated the marginal microleakage of five single step adhesives. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of extracted human molar teeth. Prepared teeth were randomly divided into five groups and restored using one of the single step adhesives and composite resins: Prompt L-Pop/Filtek Z-250 (Group 1), AQ Bond/Metafil CX (Group 2), One-Up Bond F/Palfique Toughwell (Group 3), Futurabond/Admira (Group 4), Xeno III/Spectrum TPH (Group 5). The restored teeth were thermocycled. Microleakage was assessed by dye penetration using 2% methylene blue dye solution. The teeth were bisected buccolingually and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis test and Mann-Whitney tests. The results of this study were as follows; 1. Microleakage of enamel margins in group 3 was statistically higher than that in groups 1, 2, 4, 5 (p < 0.05) 2. Microleakage of dentin margins in group 1 was statistically higher than that in groups 2, 5, and that in group 3 was statistically higher than that in groups 2, 4, 5 (p < 0.05). 3. Dentin marginal microleakage was higher than enamel marginal microleakage in all experimental groups. In conclusion, Prompt L-Pop showed the least leakage at enamel margin, and AQ Bond showed at dentin margin in this study. Marginal miroleakage in dentin was higher than that in enamel.

상아질에 적용된 재 습윤제가 미세인장 결합강도에 미치는 영향

강희영,조영곤,김종욱,박병철,유상훈,진철희,최희영,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.2

This study investigated that the effect of rewetting agent on dentinal microtensile bond strength (μTBS). Human molars were sectioned to expose the superficial dentin surfaces. Samples were divided into two groups according to type of adhesives-Single Bond (S) and One-Step (0)], and again subdivided into five groups by different dentin surface treatment-dry for 15s (D) , blot dry (BD) or dry for 15s, and rewet with different rewetting agents[distil1ed water (DW), Gluma Desensitizer (GD) and Aqua-Prep (AP)]for 30s. After application of adhesive, composite resin was built up on the bonding surface. Each tooth was sectioned to obtain stick with 1mm^(2) cross sectional area and the μTBS was determined by EZ test. In the S group, the mean μTBS of GD, AP and BD group was significantly higher than that of DW and D group (p < 0.05). In the 0 group, the mean μTBS of AP, GD, BD and DW group was significantly higher than that of D group (p < 0.05). The data suggested that Gluma Desensitizer and Aqua-Prep could be successfully used as rewetting agents, and Distilled water could be acceptable in aceton based adhesive system only.