Microstructure‑Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Soo‑Bae Kim,Young‑Hee Cho,Jae‑Gil Jung,Woon‑Ha Yoon,Young‑Kook Lee,Jung‑Moo Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al–Si alloy in a temperature range of 750–800 °Cand its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a hightemperature, which is about 100 °C above the liquidus temperature, had little effect on the grain refinement but enhanced thehomogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, α-Al and intermetallics)significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found tosuppress the formation of Cu-bearing phases, i.e., Q-Al5Cu2Mg8Si6, Al2Cuphases that form in the final stage of solidificationwhile notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increasein the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment withinthe matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanismcovering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

A simple approach to estimate the mechanical properties of collagen-like microfibrils surrounded by water

Young-june Yoon,Cheol-soo Bae,Ho-sik Park 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-

The effective Young's modulus of a microfibril surrounded by water may be simply calculated by using the upper (Voigt) and lower (Reuss) bounds. The result is compared to the Young's modulus estimated by using the Steered Molecular Dynamics (SMD) (Zhang et al. 2007). Our result shows 9.2% difference from the result estimated by SMD, but the steps using these bounds are much simpler than SMD..

부산지역 무균성 뇌막염 원인 바이러스의 분리 및 동정 : 1998년을 중심으로

김영희,정영기,김기순,지영미,윤재득,김병준,구평태,민상기,정구영,김만수,조경순 동의대학교 기초과학연구소 2000 基礎科學硏究論文集 Vol.10 No.1

The incidence of aseptic meningitis infection is ensuing and threatening the health of children. Enteroviruses are the major agents of aseptic meningitis and identification of virus has been a clue to diagnosis and epidemiology. The outbreak of aseptic meningitis occurred in Pusan, 1998. Patients were concentrated from April through November. Children were more susceptible than adults. Among 306 cases of specimens from stool, throat swab tested, only 7.2% were positive on virus isolation, 12 cases from stool and 10 from throat, respectively. All isolated 7 serotypes of viruses represented cytopathic effect on cultured cells. Three types of echovirus 6, 25, 30 and coxsackievirus B2, B3, B4, B6 were identified by neutralizing anti body test. Isolated coxsackievirus and echovirus were observed by an electron microscope with negative staining.

흰쥐 시상에서 Epidermal growth factor receptor면역반응 신경세포의 생후 발달에 관한 연구

박영란,정윤영,김종중,문정석,오재욱,정영욱,김주수 조선대학교 2003 The Medical Journal of Chosun University Vol.28 No.1

Background and Objectives : Epidermal growth factor receptor (EGFR), a 170-kDa transmembrane glycoprotein, appears to mediate epidermal growth factor (EGF) activity. Transforming growth factor-α and EGF produce their biological effects in numerous systems by stimulating the EGFR In this study, we examine the postnatal development of EGFR immunoreactivity in the different regions of the thalamus of the rat Materials and Methods : The present study is based on 28 postnatal cases of rat thalamus ranging from the day of birth, postnatal day 0 (P0) to 30 days (P3, P5, P10, P15, P20, P30), and these cases were compared with adult rat thalamus. Cryostat sections were processed free-floating with monoclonal antibody by immunohistochemistry Results : EGFR immunoreactivity in the thalamus of the rat showed very different patterns according to postnatal ages and thalamic areas. EGFR-immunoreactive cells appeared in the first two postnatal weeks, except the ventral posterior thalamic nuclei. In the early postnatal days, EGFR-immunoreactive cells appeared thalamic midline structures, increased progressively in the first two postnatal weeks, and followed mediolateral gradient. The mature patterns of EGFR-immunoreactive cells were achieved at P20 Conclusion : These data indicate that the maturation of EGFR-immunoreactive cells requires a relatively prolonged period of time to achieve an adult configuration. Many growth factors probably play protective or neurotrophic roles at EGFR-immunoreactive neurons of thalamus both young and adult rats In addition to difference in time of appearance in thalamic nuclei and developing pattern with mediolateral gradient suggest that EGFR-immunoreactivities are correlated with the appearance of the related functional.

복합재료역학을 이용한 콜라겐 단백질 마이크로피브릴의 탄성율 예측 개선

윤영준,배철수,Yoon, Young-June,Bae, Cheol-Soo 대한의용생체공학회 2010 의공학회지 Vol.31 No.3

The effective Young’s modulus of a microfibril surrounded by water may be simply calculated by using the upper (Voigt) and lower (Reuss) bounds, which is one way to estimate the Young’s modulus in composite materials. The Steered Molecular Dynamics (SMD) has been used for estimating the Young’s modulus of a microfibril surrounded by water. In this paper, the result estimated by the upper (Voigt) and lower (Reuss) bounds shows 9.2% to 21.8% discrepancy from the result estimated by SMD, but introducing “efficiency of reinforcement parameter” removes the discrepancy and shows good agreement with the result estimated by SMD. We found the best fit for the Young’s modulus against the size of the gap between microfibrils. Also the steps using these bounds are much simpler than SMD.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

제대혈 단핵구 냉동보존 기법에 따른 해동 후 세포 회복률 비교 : 급속 냉각 vs 통제속도 냉각 Dump Freezing vs Controlled Rate Freezing

오상철,김병수,윤수영,박경화,윤소영,김석진,서재홍,최철원,신상원,김열홍,김준석 대한조혈모세포이식학회 2003 대한조혈모세포이식학회지 Vol.8 No.1

연구배경: 저자 등은 조혈모세포를 -80℃ 냉동고에서 급속냉각법을 통하여 경제적으로 보존하는 방법의 냉동보존 효율이 통제속도냉각 후 액체질소보존법의 냉동보존 효율과 동등한 유효기간을 규명하고자 본 연구를 시행하게 되었다. 방법: 총 20 명의 산모에서 채집한 재대혈을 대상으로 하여 10% DMSO로 제대혈을 -80℃로 급속냉각한 경우(실험군)와 통제속도냉각장치로 냉각 후 액체질소냉동고에서 보존한 경우(대조군)에서의 해동 후 세포 회복률 및 기능의 회복 정도가 동등한 기간의 범위를 파악하기 위하여 3달 간격으로 총 18개월 동안 각 군 간의 해동 후 단핵세포회복률, CFU-GM 집락회복률, CD34+ 세포회복률 등을(평균)±(표준편차)로 표시하여 Paired t test를 통하여 비교, 분석하였다. 결과: 1) 생존 단핵세포 회복률: 대조군(통제속도냉각군)과 실험군(급속냉각군)을 비교하여 보았을 때, 모든 기간 동안 각 군 간에 유의한 차이를 발견할 수 없었다. 2) CFU-GM 집락 회복률: 대조군(통제속도냉각군)과 실험군(급속냉각군)을 비교하여 보았을 때 12개월 이후부터는 대조군이 실험군에 비하여 높은 경향의 회복률을 보였으나 양 군 간의 유의한 차이는 없었다. 3) CD34+세포 회복률: 대조군(통제속도 냉각군)과 실험군(급속 냉각군)을 비교하여 보았을 때 12개월 이후부터는 대조군이 실험군에 비하여 높은 경향의 회복률을 보였으나 양 군 간의 유의한 차이는 없었다. 결론: 제대혈에서 채집된 단핵구를 냉동보존 시 18개월까지 -80℃ 급속 냉각법으로 보존한 군과 통제속도 냉각 후 액체질소 보존 군 간에 단핵세포 회복률, CD34 양성 세포 회복률, CFU-GM 세포 회복률의 유의한 차이가 없었음을 관찰할 수 있었다. Background: This study was designed to compare the mononuclear cell recovery rate of cord blood after thawing and freezing according to cryopreservation methods: dump freezing vs controlled rate freezing. Methods: Twenty samples of cord blood were divided into dump freezing and controlled rate freezing groups. The viable mononuclear cell, CFU-GM and CD34+ cell recovery rates were evaluated at the time of post-thawing 1, 3, 6, 9, 12, 15 and 18 months after cryopreservation with 10% DMSO and compared between two groups. Results: The mean viable mononuclear cell recovery rates from cryopreservation 1 month to 18 months of dump freezing and controlled rate freezing were 81~88% and 82~89%, respectively. There was no statistical difference between two groups. The mean CFU-GM colony and CD34+cell recovery rates of dump freezing and controlled rate freezing (cryopreservation duration: 1 month to 18 months) were 66~76% vs 71~78% and 86~95% vs 86~94%, respectively. There was no statistical difference between the results of two groups. Conclusion: The -80℃ storage without rate-controlled freezing of cord blood was practically applicable with satisfactory cell recovery rates after thawing, which was comparable with those cryopreserved with controlled rated freezing and liquid nitrogen storage.

모체 Thyroxine 투여가 태아알코올효과를 가진 흰쥐 대뇌겉질 및 해마에서 NPY함유 신경세포의 생후 발달에 미치는 영향

김복,박상기,박영란,김종중,문정석,김주수,문영민,현영식,천관영,정윤영 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.2

Background and Objectives: Maternal alcohol abuse is considered to be one of the most prominent cause of neurobiological malformations in the postnatal and adult life of the offspring. In this study, we investigated the effects of maternal alcohol drinking on the postnatal development of NPY-containing neuron, and, the influence of thyroxine treatment on the cerebral cortex and hippocampus of pups of alcohol abused mother. Materials and Method: Time-pregnant rats were divided into three groups. Alcohol-fed group A received 35 calories of liquid alcohol diet daily from gestation day 6; control pair-fed group B was fed a liquid diet in dextrin replaced alcohol isocalorically: alcohol + T4 group C received 35 calories liquid alcohol diet and exogenous thyroxine subcutaneously. Results: Group C showed prominent NPY immunoreactivity in the cerebral cortex compared to group A and B at P7. In group C, NPY-containing neurons were widely distributed in the all layers of cerebral cortex after P14. Besides, numerical decrease of NPY-containing neuron as age increases was not found in group C. However, the decrease of NPY-containing neuron was clearly observed in group A compared to group C after P14. In hippocampus, group Band C were appeared similar patterns after P7. Additionally, in group C, NPY immunoreactivity was prominently appeared in CA2 and CA3 at P14 as compared to group B. Conclusions: The present results showed the increase of intensity and number of NPY-containing neurons in cerebral cortex and hippocampus of pups of exogenous T₄ supplemented alcohol-exposed dams as compared to control pair-fed and alcohol-exposed pups at P7. It presumably suggest that NPY-containing neurons might be regulated by the early postnatal growth stimulatory effect of the exogenously supplemented T₄. Therefore, the increase of NPY synthesis caused by maternal administration of exogenous thyroxine may ameliorate fetal alcohol effect, one of the ill effects as a result of the dysthyroid state following maternal alcohol abuse.

퇴행성 요추질환에서 GRAF 연성고정장치의 치료효과

하윤,김영수,윤도흠,진동규,박희완 대한신경외과학회 1998 Journal of Korean neurosurgical society Vol.27 No.10

사적 경계 영역에서 나타나는 공공성에 관한 연구

윤미섭,이영수 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(계획계)

The purpose of this study was to redefine the publicity and analysis how to operate in contemporary society. Because of relation inside and outside, privacy and publicity, interface is important in city landscape. In this buffer zone it become limitless as liminal space. We can percept another person so though this feel the publicity in this space. It indicates that the center of awareness shift from body to consciousness and bridge the grab between exterior and interior not though materials or design on special devices but though the plan and though flowing nature. So it's so simple and pure. After all, consciousness of the stranger extend to percept self-consciousness in soft boundary.