Microstructures and Mechanical Properties of Multiphase‑Reinforced In Situ Aluminum Matrix Composites

Ju‑Hye Kim,Jae‑Gil Jung,Eun‑Ji Baek,최윤석,Kwangjun Euh 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2

We investigated the microstructures and mechanical properties of multiphase-reinforced in situ aluminum matrix composites(AMCs) prepared with various combinations and contents of Li, Mg, Si, Cu, Zn, Sn, and Ni. The area fractions of thesecondary phases in the as-cast AMCs ranged from 26% to 58%, and the types of secondary phases depended on the alloychemical compositions. The type and amount of secondary phases were more important than matrix strengthening in determiningthe alloy mechanical properties. Composite hardness and compressive stress increased while fracture strain decreasedwith increasing total area fraction of the secondary phases up to 40%. The formation of coarse primary and soft/heavySn-containing phases significantly deteriorated the alloy mechanical properties. Annealing also influenced the mechanicalproperties of the AMCs by changing the microstructures of the secondary phases and Al matrices.

용도지역 면적산정방식의 평가에 관한 연구

백기영,박은주 永同大學校 1997 硏究論叢 Vol.3 No.1

도시계획에 있어 용도지역의 면적산정은 지역지구제 운용의 핵심적 요소이다. 현행 법정 도시계획에 있어 사용되고 있는 용도지역 면적 산정방식을 유형화하고 평가·분석한 본 연구의 결과 현행 법정 도시계획의 입안과정에서 용도지역 면적산정과정은 방식이 통일되어 있지 않고 세부적 지표의 활용에 있어서도 다양함을 보이고 있다. 향후 도시계획에 있어 면적산정 적용방식과 적용단계별 지표적용의 기준정립이 시급한 것으로 분석되었다. Estimating an area of each zoning is an essential element on zoning application in urban Planning. This paper aims at valuation, analysis, and categorization of methods used in present legal urban and land use planning. The results of this paper are as follows. The Methods are not standard in estimating an area in legal urban planning, and an index by stages. Hereafter these are urgent questions, establishment of standard index by stages and estimating an area of each zoning

반코마이신 내성 장구균 감염에 대한 quinupristin-dalfopristin 치료 경험

추은주,최상호,조영환,정선미,김백남,김남중,김미나,김양수,우준희,류지소 대한화학요법학회 2002 대한화학요법학회지 Vol.20 No.1

VRE 감염이 중환자에서 급속히 증가하고 있으나 이에 대한 확실한 치료제가 없어 새로운 항생제에 대한 활발한 연구가 있는데 그 중 하나가 quinupristin/dalfopristin이고, 저자들은 중증 환자들의 VRE 감염에 대해 quinupristin/dalfopristin를 투여하여 치료한 임상적 경험을 하였기에 문헌고찰과 함께 보고하는 바이다. Vancomycin-resistant enterococci (VRE) was first recognized in 1992 in Korea. VRE infection have been increasingly reported in immunosuppressed patients over the past decade and have become one of major nosocomial pathogens. Clinicians carings for patients with VRE infections face severe constraints in the selection of treatment. Quinupristin/dalfopristin is active in vitro againt vancomycin-resistant E. faecium (VREF), with a MIC_(90) of 1.0㎍/mL. We studied the clinical efficacy and safety of this agent in the treatment of VREF infection. Patients were included if they had signs and symptoms of active infection including bacteremia, intra-abdominal infection, and wound infection. A total of 13 patients with VREF infection were enrolled. A favorable clinical response (cure or improvement) occured in 10 of 11 evaluable patients. The only adverse events related to quinupristin/dalfopristin were arthralgia and myalgia, which occurred in 2 of 13 patients. These results suggest that quinupristin/dalfopristin is effective and safe as treatment for VREF infections in critically ill patients with serious underlying conditions.

Caffeine이 지구성 운동 수행능력에 미치는 영향과 억제성 아미노산에 의하여 활성화되는 이온통로의 조절작용

김은경,김영표,천병옥,이계영,김연정,임백빈,조영욱,김창주,김성수 대한스포츠의학회 1999 대한스포츠의학회지 Vol.17 No.1

To investigate the effect and mechanism of caffeine on endurance exercise, two experiments were performed. First, to test caffeine effect on aerobic exercise, 200-300g Sprague-Dawley rats were used and three groups, control group, low caffeine injection group and high caffeine injection group, were divided. Blood smpling by heart puncture were done at rest, after 30 min treadmill exercise, and after maximal exercise. Blood glucose, free fatty acid concentration were detected and following results were obtained. Glucose concentration showed significant difference between groups(p=0.0305) and also significant changes were exhibited between time(p=0.0004). Free fatty acid concentration had no difference between groups. but had significance between times(p=0.00065). Exercise endurance performance time showed significant difference(p=0.02350 in high caffeine injection group compared to control group. In this experiments, endurance exercise capacity was increased by caffeine injection. Therefore, second experiment was performed to investigate the effect of caffeine on ion current induced inhibitory amino acid neurotransmitter. GABA and glycine. Single periaqueductal gray neuron was acutely dissociated and nystatin perforated patch clamp was performed under voltage clamping condition. Caffeine evoked outward current in PAG neuron dose dependent manner. 1mM of caffeine application had no response. but 3mM caffeine evoked about 32.5±8.539pA outward ion current and 10mM caffeine evoked about 215.46±19.4pA outward current. 10^-2mM GABA activated Cl￣current and recorded by inward current. Caffeine inhibited GABA activated Cl￣ current concentration dependent manner. 10^-2mM of caffeine had no effect on 1-^-2mM of GABA response. but 10^-1mM caffeine inhibited GABA activated Cl￣ current about 5.74±2.13%, 1mM caffeine inhibited about 17.25±2.70%, 10mM caffeine inhibited GABA response about 45.31±7.71%. 10^-1mM of glycine activated Cl￣ current and also recorded by inward current. Caffeine inhibited glycine activated Cl￣ current concentration dependent manner. 10^-2mM caffeine decreased glycine activated Cl￣ current about 4.61±1.650%, 10^-1mM caffeine decreased about 6.49±2.24%, 1mM caffeine decreased about 26.82±4.27%, and 10mM caffeine decreased glycine response about 94.47±1.39%. These results suggest that caffeine inhibite inhibitory amino acid, GABA and glycine, this response causes excitation of CNS and this seems to be the basic mechanism of increasing effect to aerobic exercise performance by caffeine.

오매(Fructus Mume)의 항산화물질의 분리 및 특성연구

황현주,안은미,백남인,조재선,김해영 경희대학교 생명자원과학연구원 1998 硏究論文集 Vol.19 No.-

천연물로부터 새로운 항산화제를 개발하기 위한 연구의 일환으로 한방에서 사용되는 한약재 중의 하나인 오매(烏梅)의 물 추출물과 메탄을 추출물 및 순차 분획물에 대해 팜유, 우지와 돈지를 기질로하여 유지저아시험, Rancumat method, 전자공여작용 등으로 항산화성을 확인한 결과, EtOAc 분획물에서 강한 항산화 활성을 나타내어 column chromatography, thin layer chromatography를 통하여 활성성분에 관한 연구를 시도하였다. 1. 오매 용매분획물 중 EtOAc 분획물(400 ppm)은 유지저장실험(60℃)에서, 팜유, 우지와 돈지에 모두 우수한 효과를 나타내었으며, 특히 우지에서 높은 활성을 나타내었고, BHA(200 ppm)와 α-tocopherol(200 ppm)보다 활성이 높았다. 2. 오매 EtOAc 분획물(400 ppm)은 Rancimat method에서는 팜유, 우지와 돈지에 비교적 우수한 효과를 나타내었으며, 우지에서 AI가 4.39로 상당히 높은 활성을 나타내었다. 3. 오매의 용매분획물 중 EtOAc 분획물이 DPPH라디칼에 대한 강한 소거활성을 나타내었으며, 그 활성은 EtOAc 분획물의 농도에 의존하여 증가하였고, SC_(50)은 21.2μg/ml이었다. 4. 오매 EtOAc 분획물에서 분리한 8개 획분 중 E4에서 SC_(50)이 16.7μg/ml으로 높은 DPPH 라디칼 소거활성을 나타내었으며, 원인 물질은 여러 가지 스펙트럼 측정 결과 수종 물질이 혼합물인 것으로 밝혀져, 보다 순수한 형태로의 분리 후 정확한 동정의 시도가 요구되었다. Fructus Mume is the roasted hits of Prunus mwme and has been used as tradibonal Chmese medicine. The anboxidatwe effect of the extract from Fructus Mume was measured using different methodsn such as, electron donating abdihes(EDA), Rancimat and oven tests. The methanol extract obtained from the Fructus Mume was solvent-fractionated with ethyl acetate, n-butanol and water, respectively. The ethyl acetate fraction showed the highest antioxidative activity among them. To identify the compounds with antioxidative activity, the isolates from thm layer chromatography were studied further. This study demonstrates that Fructus Mume might be useful for the prevention or treatment of disorders associated with oxidative damage.

근적외분광분석법을 이용한 참기름 정량 분석 및 진위 판별

서은정,백주현,우영아,김효진 동덕여자대학교 종합약학연구소 2002 동덕약학연구지 Vol.6 No.-

In this study, sesame oil have been analyzed by near infrared spectroscopy (NIRS). Sesame oil was mixed with the other edible oil. NIR transmittance spectra of sesame oil mixtures were acquired by using a dip probe. Partial least squares regression (PLSR) was applied to develop a calibration model over the spectral range 1100-1750nm. The calibration model predicted the content of sesame oil for validation set with a standard errors of prediction (SEP) of 0.3871%. Soft Independent Modeling of Class Analogy (SIMCA) was used to identify sesame oil and adulteration. This model identified the sesame oil and adulteration for validation set with 100% accuracy. This study showed that the rapid and non-destructive the determination of the quantitative analysis of sesame oil, the identification of sesame oil and adulteration was successfully performed by portable NIR system.

2003년 국내 중증급성호흡기증후군 진료 현황 및 문제점 분석

이진수,김은실,정문현,백제중,정선화,안주희,최영화,이선희,고철우,김성범,김민자,박승철,기현균,송재훈,최상호,김양수,이상오,조용균,박영훈,정숙인,김연숙,이흥범,손창희,장성희,정희진,김우주 대한감염학회 2004 감염과 화학요법 Vol.36 No.3

목적 : 2002년 말 중국에서 SARS가 발생한 이후 국내에서도 2003년 10월까지 총 3명의 추정환자, 17명의 의심환자가 보고되었다. 향후 추가적인 SARS의 유행이 우려되는 상황에서, 그간의 SARS 환자 진료에 있어서의 실질적인 준비사항, 진료 현황 등에 대한 조사를 통해 문제점을 파악하여, 향후 더 나은 대비가 될 수 있도록 개선점을 제시하고자 하였다. 재료 및 방법 : SARS로 의심되는 환자를 진료 경험이 있는 병원의료진을 대상으로 2003년 10월에 설문조사를 실시하였다. 설문에는 SARS 환자 진료 시의 실질적인 조치, 진료 현황, 병실, 응급실 및 외래에서의 격리 시설과 준비사항, 보건당국의 관리와 지원에 관한 사항을 포함하였다. 결과 : 대상이 되는 22개 병원 중 17개(17/22, 77.2%) 병원이 설문에 응하였다. SARS 환자를 위한 격리실은 응급실, 외래, 일반병실 및 중환자실에서 각각 9개(9/17, 52.9%), 5개(5/17, 29.4%), 15개(15/16, 93.7%), 4개(4/16, 25%) 병원에서 음압처리가 되어있지 않은 일인실 혹은 다인실이 사용되었고, 1개(1/16, 6.3%) 병원에서만 일반병실에서 음압격리실이 운영되었다. 입원환자의 진찰 시 개인보호구의 착용은 거의 모든 의료기관에서 이루어졌다. 보건당국에서 SARS지정병원의 시설 등을 사전에 확인한 곳은 1곳(1/12, 8.3%)이였고, 14개 병원(14/15, 93.3%)에서는 보건당국에 의뢰한 검사결과를 통하 받지 못하였다. 결론 : 의료기관에서 SARS 환자용 격리실뿐만 아니라 기존의 격리실 설비 등이 미흡하였으며, 특히 중환자실 및 외래의 준비가 더욱 부족하였다. 보건당국의 의료기관에 대한 종합적인 지원이 부족하였고, 병원과의 원활한 연계가 잘 이루어지지 않았다. SARS 만이 아닌 격리를 필요로 하는 질환의 적절한 진료를 위해 향후 병원 시설의 정비와 정부차원에서의 보다 구체적이고 실질적인 대책마련이 필요하다. Background : There was an worldwide outbreak of the Severe Acute Respiratory Syndrome (SARS) originated from China in late 2002. During that period three cases of suspected SARS and 17 cases of probable SARS were reported in Korea. With the concerns about the reemergence of SARS-coV transmission, it is important to be prepared for any possibility. So, this study is aimed to analysis the past measures in managing SARS and propose the amendatory plans to improve the preparedness. Materials & Methods : Questionnaires were collected among clinicians with any experience in managing the probable or suspected SARS cases in Oct. 2003. 17 out of 22 hospitals responded to the questionnaire. The contents in the questionnaire were practical activities, personal equipments, response plans, isolation facilities in emergency centers, outpatient clinics, general wards and intensive care units, and relationship with the public health department. Results : The dedicated isolation rooms in emergency centers, outpatient clinics, general wards, and intensive care units were prepared in 9 (9/17, 52.9%), 5 (5/17, 29.4%), 15 (15/16, 93.7%), and 4 (4/16, 25.0%) hospitals, respectively. Except for one hospital that newly made negative pressure room for SARS, single or multi-bed rooms without airborne infection control were used in all the other hospitals. The personal precaution principles were kept quite well in general wards. Before the designation of SARS hospital by the public health department prior evalution to see if the hospital was suitable for managing SARS was conducted in only 1 (1/12, 8.3%) hospital. The results of laboratory diagnosis were reported back in 1 (1/15, 6.6%) hospital. Conclusions : The isolation facilities which can control airborne infection were almost deficient not only for SARS but also for other respiratory transmissible diseases. For the infection control of transmissible diseases including SARS, more investment is needed on medical facilities and comprehensive support from the public health department required.

Stroma-free mass production of clinical-grade red blood cells (RBCs) by using poloxamer 188 as an RBC survival enhancer

Baek, Eun Jung,Kim, Han-Soo,Kim, Ju-Hye,Kim, Nahn Ju,Kim, Hyun Ok Blackwell Publishing Inc 2009 Transfusion Vol.49 No.11

<P>BACKGROUND: </P><P>In vitro generation of red blood cells (RBCs) is an important alternative to donor RBCs. It was impossible, however, to generate a large quantity of RBCs due to necessity of supporting stromal cells or xenogeneic or human serum for in vitro culture, which had restrictions in safety, supplies, and expenses. In addition, the low viability of erythroblasts during terminal maturation in vitro required highly efficient production protocols. Here, we present a protocol for mass production of clinical-grade RBCs from cord blood (CB) CD34+ cells in stroma-free culture by using poloxamer 188 (P188), a polymer known to be cytoprotective against hydrodynamic stress.</P><P>STUDY DESIGN AND METHODS: </P><P>Umbilical CB CD34+ cells were cultured for 21 days in medium containing several cytokines, and roughly fibrin-eliminated CB derived plasma was added from Day 13. To enhance the final RBC production, P188 was added from Day 13 and the cell count and viability were compared with controls lacking P188.</P><P>RESULTS: </P><P>Erythroid expansion between Day 17 and Day 21 was significantly higher in cultures treated with P188, with a mean of 1.5 times and maximum of 3.6 times higher expansion than in controls lacking P188. The enhanced survival resulted from increased stability of the RBC membrane and decreased fragility. The erythroid cells were enucleated up to 95% and demonstrated hematologic variables similar to those of reticulocytes.</P><P>CONCLUSION: </P><P>This RBC production protocol is a simple stroma- and serum-free culture method ensuring enhanced viability of terminally mature erythroid cells and can be easily applicable to mass production of clinical-grade RBCs as well as erythropoiesis research.</P>

The Production of Oxygen Free Radicals by Cyanate in Cultured Osteoblast Cell

( Eun Ju Chang ),( Chul Min Baek ),( Kyo Cheol Mun ),( Hye Jung Choi ),( Eun Ah Hwang ),( Seung Yeup Han ),( Sung Bae Park ),( Hyun Chul Kim ) 대한신장학회 2004 춘계학술대회 초록집 Vol.24 No.1

Effect of Amino Acids on the Survival of Osteolastic Cells

( Eun Ju Chang ),( Chul Min Baek ),( Kyo Cheol Mun ),( Hye Jung Choi ),( Eun Ah Hwang ),( Seung Yeup Han ),( Sung Bae Park ),( Hyun Chul Kim ) 대한신장학회 2004 춘계학술대회 초록집 Vol.24 No.1