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.-

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.

후두부 발작성 간질파와 동반된 양성 소아기 간질의 임상적 연구

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

국내육성 오차드그라스 품종들의 캘러스 형성율 및 식물체 재분화 효율

김기용,강경민,배은경,이인애,임용우,최기준,박근제,손대영,조진기 Plant molecular biology and biotechnology research 2003 Plant molecular biology and biotechnology research Vol.2003 No.-

Comparisons of callus formation ratios from seed explants, callus sizes, regeneration ratios from callus and regeneration efficiency for 4 orchardgrass (Dactylis glomerata L.) varieties (Three were developed in Korea and one was imported from foreign nation) are as follows; Jangbeol 102 (67.0%) has the highest callus formation ratio in 4 weeks incubated callus after bedding the seed explants, but Potomac (68.4%) has the highest ratio in 6-seek callus. Potomac (3.93cm) has the highest callus size in 4-week callus, but Jangbeol 101 (4.32cm) has the highest size in 6-week callus. Jangbeol 101 (17.7%) has the highest plant regeneration ratio in 4-week callus, but Potomac (37.4%) has the highest raion in 6-week callus. Jangbeol 102 (11.5%) has the highest plant regeneration efficiency in 4-week callus, but Potomac (25.6%) has the highest efficiency in 6-week callus.

Mg₂SiO₄ : La, Ho 열형광선량계에서 활성제 농도가 글로우 커브에 미치는 영향 La, Ho TLD on Activation Concentration

김영국,손인호,채건식,노경석,오재근,이은숙 경남대학교 신소재연구소 1996 論文集 Vol.6 No.-

본 연구에서는 Mg₂SiO₄에 활성화 물질로 La, Ho를 첨가하여 열형광체를 제작하였고 불순물의 농도를 1wt.% ∼5 wt.%까지 변화시키면서 열평광강도의 glow curve를 측정하였다. 도한 열형광체의 glow curve를 peak shape법으로 분석해서 TL특성에 대한 포획 매개변수와 활성화 에너지, 발광차수, 선량의존성등을 조사하였으며, 그 물리적 특성을 조사하고 선량계로서 타당성과 실용성을 확인하였다. The Mg₂SiO₄: La, Ho thermoluminescent phospher has been prepared by sintring Mg₂SiO₄after doping the transition elements La and Ho. The heating rate is 10℃/sec at this thermoluminescent phospher are heated. The maximum peaks are found in the measured Mg₂SiO₄: La and Ho. TL glow curve at 229℃ and 345 C when the 1 wt.%-5 wt.%. The glow curve of TLD increased TL intensity and temperature of peak appears to the high temperature when the heating rate is l0℃/sec-25℃/sec. The activation energy of the main peak has been estimated by the peak shape method. The estimated activation energies are 1.77 eV. 1.52 eV respectively. The thermoluminescence process in Mg₂SiO₄: La and Ho are found to the 2nd order when the main peak of the glow curve is analyzed by peak shape method. The dose responses of Mg₂SiO₄: La and Ho TLD are linear up to intensity of X-ray.

담관 낭선암 1례

박건욱,홍기봉,정재열,노명환,한상영,최석렬,신우원,나서희 동아대학교의과대학 1997 동아의대학술지 Vol.9 No.1