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>

A Study on Bias Effect on Model Selection Criteria in Graphical Lasso

Young-Geun Choi,Seyoung Jeong,유동현 계명대학교 자연과학연구소 2018 Quantitative Bio-Science Vol.37 No.2

Graphical lasso is one of the most popular methods to estimate a sparse precision matrix, which is an inverse of a covariance matrix. The objective function of graphical lasso imposes an 1 A study on Bias Effect on Model Selection Criteria in Graphical Lasso Young-Geun Choi1, Seyoung Jeong2, Donghyeon Yu2* 1SK Telecom, Seoul 04539, Korea 2Department of Statistics, Inha University, Incheon 22212, Korea (Received Oct 8, 2018; Revised Nov 4, 2018; Accepted Nov 12, 2018) Abstract Graphical lasso is one of the most popular methods to estimate a sparse precision matrix, which is an inverse of a covariance matrix. The objective function of graphical lasso imposes an ℓ-penalty on the (vectorized) precision matrix, where a tuning parameter controls the strength of the penalization. The selection of the tuning parameter is practically and theoretically important since the performance of the estimation depends on an appropriate choice of tuning parameter. While information criteria (e.g. AIC, BIC, or extended BIC) have been widely used, they require an asymptotically unbiased estimator to select optimal tuning parameter. Thus, the biasedness of the ℓ- regularized estimate in the graphical lasso may lead to a suboptimal tuning. In this paper, we propose a two-staged bias-correction procedure for the graphical lasso, where the first stage runs the usual graphical lasso and the second stage reruns the procedure with an additional constraint that zero estimates at the first stage remain zero

National Security Policies : Reciprocity in South Korean Security Policy Vis-a-vis North Korea and the United States

김영근 ( Young Geun Kim ) 경남대학교 극동문제연구소 2013 ASIAN PERSPECTIVE Vol.37 No.2

I review the principle of reciprocity in South Korean security policy with regard to North Korea and the United States and analyze how the principle fits with US security policy concerning South Korea. Diffuse reciprocity shaped Korean security policy starting with President Kim Dae-jung`s Sunshine Policy. The Lee Myung-bak government`s hard-line approach increased military tension and economic anxiety on the peninsula. The new South Korean government under Park Geun-hye should devise achievable policy measures rather than place excessive pressure or unrealistic demands on North Korea.

유산균들의 콜레스테를 저하성, 내산성, 내담즙성, 항생제 내성 비교

박소영,고영태,정후길,양진오,정현서,김영배,지근억 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

기능성 요구르트의 제조에 사용되는 유산균은 인체에 유익한 생리활성과 우수한 생존능력을 보유하고 있는 것이 바람직하다. 본 연구에서는 다양한 유산균주의 산과 담즙 및 항생제에 대한 내성을 조사하였으며 in vitro에서 콜레스테롤 저하능을 조사하였다. In vitro에서 콜레스테롤 저하능이 우수한 13균주를 선발하여 이들의 동결건조 분말을 고 콜레스테롤 식이의 실험쥐에 투여하였다. 그 결과 8균주는 비 투여구보다 유의적으로 18.3~27.3%의 콜레스테롤 저하능을 나타냈다(P≤0.05). 이들 중에서 Bifidobacterium infantis AM-220, Lactobacillus AM-245, Streptococcus MA-1의 3균주를 이용하여 요구르트를 제조한 후 동결건조 분말을 이용하여 급여실험을 수행한 결과, 총 콜레스테롤과 LDL 함량이 유의적으로 감소하는 것으로 나타났다. For a probiotic yoghurt it is desirable to utilize lactic acid bacteria with a high survival rate and beneficial function to human beings. We have examined a variety of lactic acid bacteria to assess the acid and bile tolerance and antibiotic resistance. In addition, an in vitro culture experiment was performed to evaluate their ability to reduce cholesterol levels in the growth medium. Thirteen strains were selected from in vitro cholesterol assays and fed to Sprague-Dawley rats with a high-cholesterol diet. Among the 13 strains tested, 8 strains were shown to reduce serum cholesterol levels significantly after 24 days of administration in vivo. Rats were fed lyophilized yoghurt powder fermented with a combination of 3 selected strains: Bifidobacterium infantis AM-220, Lactobacillus AM-245, and Streptococcus MA-1. The levels of total cholesterol and low density lipoprotein were significantly lower (p≤0.05) in rats fed the yoghurt powder compared with control group. These studies suggest that yoghurt fermented with appropriately selected lactic acid bacteria may have a anticholesterolemic effect.

당류중에서 일산화탄소의 발생에 관한 연구

박성우,김남이,서중석,최영남,이광영,양영근 內務部 國立科學搜査硏究所 1996 國立 科學 搜査 硏究所 年報 Vol.28 No.-

후두부 발작성 간질파와 동반된 양성 소아기 간질의 임상적 연구

유영수,이상도,김지언,임정근,박영춘 대한신경과학회 1996 대한신경과학회지 Vol.14 No.4

강전계하에서 PZT-BYF계의 압전 및 유전특성에 미치는 영향

이영근 한국교통대학교 2014 한국교통대학교 논문집 Vol.49 No.-

The 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y1-xFex)O3 [PZT-BYF(x)] (x=0.0-0.3) piezoelectric ceramics have been synthesized by using a modified conventional solid-state method. The effects of BYF(x) addition on the phase formation, microstructure, and piezoelectric/dielectric properties were evaluated. In addition to these measurements, the piezoelectric voltage constant (g33) and the piezoelectric transduction coefficient (d33×g33) were measured in order to evaluate the essential criteria for an energy-harvesting material. With increasing content of Fe2O3 in the BYF(x) system, the piezoelectric and the dielectric properties were significantly improved. At a sintering temperature of 1,170ºC, the piezoelectric and the dielectric properties of PZT-BYF(x) ceramics showed desirable values; this resulted in a significantly higher transduction coefficient. The compositions of PZT-BYF(0.1), PZT-BYF(0.2), and PZT-BYF(0.3) showed a considerably lower ε33T value, but higher d33 and kp values. Therefore, within the concentration limit of x = 0.1 to 0.3 moles of Fe2O3, the g33 and the d33×g33 values were improved significantly. The maximum transduction coefficient of 20,167×10-15 m2/N was obtained from the composition of PZT-BYF(0.3), while the maximum tip displacement of 7.9㎛ was obtained from MPB composition of PZT-BYF(0.2) under alternative electric field.

Polyethylene film의 열자극 전류와 열 Iuminescence에 의한 전도기구

김영전,장충근,이종규 충남대학교 자연과학연구소 1989 忠南科學硏究誌 Vol.16 No.1

In order to investigate the nature and the origins of carrier trap in linear low density polyethylene. thermally stimulated Current(TSC) and thermoluminescence(TL) were investigated simultaneously by X-ray irradiation and electric field excitation in the temperature range 115∼350K. From the analysis of experimental curves and relaxation processes, the most of TSC and TL peaks well correspond to the onset of molecular motion. The peak due to the release of electron(holes) from traps formed by the polyethylene chain themselves were suggested. The main kinetic parameters related to a TL curve and the trapping parameters from TSC were evaluated by using the numerical curve fitting method. Considering the modified energy band model of amorphous, the trap energy level diagram of linear low density polyethylene was obtained.

뇌에 양극성 전기응고강도의 효과와 시간경과에 대한 실험적 연구

송근성,이영우 부산의대 1988 부산의대잡지 - 부산대학교 의과대학 Vol.28 No.2

용도 지역의 실태에 따른 상세 계획의 운용 지침에 관한 연구

김영하,이원근 단국대학교 1998 論文集 Vol.32 No.-

Korea has a two-tier legal system concerning physical urban enviroment : urban planning act and building act. The urban planning act is concerned with overwall directions of the land use in a whole city. On the other hand, building act is a regulation-orented system which deals mainly with the minimum criteria of building construction. Unfortunately, both act had many limitations to a making desirable living enviroment at the district level. Both, in general, do not count three-demensional, complex, and diversified urban enviroment. In order to overcome these limitation of general legal system, this study is problems of Zoing regulation in city, that is concentration analysis on the coverage and capacity of scales the present condition. And the analysis of use Zoing to urban present conditions. And several problems remain in the application of this new planning system, such as limited scope of the system and the shortage of necessary implementation tool. The study get hold of policy recommendation and future direction for proper implementation of this new system.