Microstructure, Tensile and Fatigue Properties of Al–5 wt.%Mg Alloy Manufactured by Twin Roll Strip Casting

Joon‑Young Heo,Min‑Seok Baek,Kwang‑Jun Euh,Kee‑Ahn Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5

This study investigated the microstructure, tensile and fatigue properties of Al–5 wt.%Mg alloy manufactured by twin rollstrip casting. Strips cast as a fabricated (F) specimen and a specimen heat treated (O) at 400 °C/5 h were produced andcompared. In the F specimen, microstructural observation discovered clustered precipitates in the center area, while in theO specimen precipitates were relatively more evenly distributed. Al, Al 6 (Mn, Fe), Mg 2 Al 3 and Mg 2 Si phases were observed. However, most of the Mg 2 Al 3 phase in the heat-treated O specimen was dissolved. A room temperature tensile test measuredyield strength of 177.7 MPa, ultimate tensile strength of 286.1 MPa and elongation of 11.1% in the F specimen and167.7 MPa (YS), 301.5 MPa (UTS) and 24.6% (EL) in the O specimen. A high cycle fatigue test measured a fatigue limit of145 MPa in the F specimen and 165 MPa in the O specimen, and the O specimen achieved greater fatigue properties in allfatigue stress conditions. The tensile and fatigue fracture surfaces of the above-mentioned specimens were observed, and thisstudy attempted to investigate the tensile and fatigue deformation behavior of strip cast Al–5 wt.%Mg based on the fi ndings.

고감도 Ames test(microsuspension assay)와 임파구 소핵시험법을 이용한 변이원성에 관한 조사 연구

안지영,김해준,윤인재,성영자,김영환,장영철 大韓産業醫學會 1996 대한직업환경의학회지 Vol.8 No.3

In order to evaluate the mutagenic effects of extractable indoor air pollutants (organic matters), we measured the mutagenic activities by sensitive microsuspension Ames test using new tester strains (YG 1024 and YG 1029). And additionally to evaluate the mutagenic effects on vital cell, we examined the frequencies of micronucleus appearing in lymphocytes from dye handling workers and controls. This study was conducted from Jan. to May, 1995. The extractable indoor air pollutants were collected by low volume air sampler in a general office room and 3 of dye handling factories. And the environment of general office room divided into 3 different groups according to the type of room heaters. To determine the frequencies of micronucleus appearing in lymphocytes, we sampled peripheral venous blood from 20 of dye handling workers and 20 of controls, and cultured, and then examined the lymphocytes. The results obtained were as follows: 1. The indirect mutagenic activities of extractable organic matters from suspended particulates collected in a general office room were higher than the direct one. 2. The strain YG 1024 was the most sensitive, and the increasing order of test strains that showed higher number of revertant were YG 1024, YG 1029, TA 100, TA 98. 3. In the general office room, the room using kerosene heater showed the highest mutagenecity, and the next was buthan gas heater, and non-heating room in order. 4. The mutagenic effects of suspended particulates in dye handling factories on the strain YG 1024 was 1.2 times higher than YG 1029. 5. The frequencies of micronucleus appearing in lymphocyte of the circulating blood of dye handling workers and the control were 5.65±2.97‰ and 4.65±0.97‰, respectively. And the difference was statistically significant.

대회향유래 Phenylpropene 화합물 trans-anethole의 3종 위생해충에 대한 살충활성

안용준 서울대학교 농업개발연구소 2000 농업생명과학연구 Vol.4 No.-

The insecticidal activities of methanol extracts from 27 aromatic plant species and five essential oils against female adults of Blattella germanica (L.) were examined by direct contact application. Because of potent insecticidal activity of methanol extract from fruit of the Illicium vernum against B. germanica female adults, the insecticidal constituents of the plant were investigated. The biologically active constituent of the Illicium fruit was characterized as the phenylpropene trans-anethole by spectroscopic analysis. The toxicity of trans-anethole to adults of B. germanica, Culex pipiens pallens (Coquillett), and Musca domestica (L.) was determined by direct contact application. Responses were dependent on the insect species and dose. In a filter paper diffusion test, trans-anethole caused 76.7 and 100% mortality at 0.159 mg/cm2 and 3.3 and 100% at 0.050 mg/cm2 against B. germanica female and male adults, respectively. Against C. pipiens pallens female adults, at 0.156 mg/cm2 , trans-anethole showed 100% mortality at 1 DAT. Against M. domestica female adults, trans-anethole gave 100 and 69% mortality at 0.796 mg/cm2 and 0.597 mg/cm2 within 1 DAT, respectively. The insecticidal activities of trans-anethole against B. germanica female adults were compared with those of three commercial insecticides (DDVP, deltamethrin, and hydramethylon), using direct contact application and fumigant test. trans-Anethole showed lower toxicity than three commercial insecticides in direct contact application but appeared higher toxicitythan deltamethrin in fumigant test. As a naturally occurring insect-control agent, I. Vernum fruit-derived materials described could be useful for managing populations of B. germanica, C. pipiens fallens, and M. domestica.

만성 B형 간염에서 라미부딘 치료중 발생한 Viral Breakthrough 예의 임상 결과

안수현,장윤정,오성남,최도원,백수정,정원석,최창원,김경오,임형준,조남영,박종재,김재선,박영태,이명석,연종은,변관수,이창홍 대한간학회 2002 Clinical and Molecular Hepatology(대한간학회지) Vol.8 No.4

목적: 만성 B형 간염의 치료 중 발생하는 약제 내성 변이종은 임상적으로는 치료 중 음전되었던 혈청 HBV DNA가 다시 양전되는 viral breakthrough 로 진단할 수 있다. 현재 약제 내성 변이종이 발생했을 경우라도 라미부딘 치료를 계속 유지하는 것을 권장하고 있으나, viral breakthrough 발생 예들의 장기적 임상경과가 아직도 불명확하여 이것을 일반화하기는 어려운 상황이다. 이에 라미부딘 사용 중 viral breakthrough 가 발생한 예들을 대상으로 그 임상경과를 알아보고자 하였다. 대상과 방법: 9개월 이상 라미부딘을 투약한 만성 B형 간염 환자로 viral breakthrough가 발생한 74명을 대상으로 하였다(남/여 54/20, 평균연령 42세). Viral breakthrough 후 혈청 ALT치, 총 빌리루빈치, HBV DNA 역가, HBeAg, anti-HBe를 정기적으로 검사하면서 임상경과를 관찰하였다. Viral breakthrough 후 라미부딘의 투약기간은 평균 13개 월(1-41개월)이었다. 결과: Viral breakthrough 발생후 혈청 ALT치가 정상으로 유지되었던 환자는 8예(11%)에 불과했고 나머지 66예(89%)에서는 ALT치가 증가하였으며, 이중 30예(41%)에서 급성 악화(ALT 정상 상한치의 5배 이상 상승)를 보였다. 급성악화는 viral breakthrough 후 3개월 내에 19예 (63%)에서 발생하여 3개월 내에 발생한 예가 많았으나 12개월 이상 지나서 나타나는 예도 약 20%에서 있었다. 비대상성 악화는 6예에서 관찰되었다. Viral breakthrough 후 급성악화가 일어난 예와 없었던 예의 비교에서 급성악화를 예측할 수 있는 인자는 발견할 수 없었다. Viral breakthrough 후 발견할 수 없었다. Viral breakthrough 후 HBeAg이 음전된 예는 8예(11%)였으나 그 임상경과는 양호하지 않았다. 결론: 만성 B형 간염 환자 에서 라미부딘 투여 중 발생한 viral breakthrough 예 중 상당수에서 급성악화가 발생하였으며, HBeAg 이 소실되더라도 그 임상경과는 양호하지만은 않았다. Viral breakthrough 발생 후 주의 깊은 임상경과 의 관찰이 요구되며, 앞으로 viral breakthrough 후 급성악화 예에 대한 대규모 연구와 적절한 치료방향의 제시가 이루어져야 할 것으로 생각된다. Background/Aims: Long-term lamivudine therapy can induce the emergence of lamivudine resistant hepatitis B virus (HBV) mutants. Clinically emergence of the mutant is expressed by the reappearance of disappeared HBV DNA in serum. Continued lamivudine treatment has been usually recommended in cases of viral breakthrough. However, the clinical outcome in patients with viral breakthrough is not clear. The aim of this study was to investigate the clinical course of chronic hepatitis B patients after viral breakthrough during lamivudine therapy. Methods: A total of 74 patients with chronic hepatitis B who showed viral breakthrough after at least 6 months of lamivudine treatment were included in this study. They had positive HBeAg and HBV DNA before treatment. The median follow-up duration after breakthrough was 13 months. Results: After viral breakthrough, only 8 patients (11%) maintained normal ALT levels and 66 patients (89%) showed elevation of ALT. 30 patients (41%) showed acute exacerbation of hepatitis (ALT increase over five-times upper normal limit). These acute exacerbations occurred within three months after breakthrough in 19 patients (63%). In the cases of acute exacerbation, 6 patients showed decompensated progression such as elevation of serum total bilirubin. One of them died of hepatic failure. A predictive factor for acute exacerbation was not found. HBeAg seroconversion occurred in 8 patients after viral breakthrough but their clinical course was highly variable. Conclusions: Chronic hepatitis B patients who had viral breakthrough during lamivudine therapy should be followed carefully and regularly in mind of potential clinical deterioration. New strategies are needed to manage the cases of acute exacerbation after viral breakthrough.(Korean J Hepatol 2002;8:389-396)

가정환경에 따른 초등학생의 한약 이용 실태에 관한 연구

안영준,박태숙 朝鮮大學校 附設 醫學硏究所 2008 The Medical Journal of Chosun University Vol.33 No.2

Background and Objectives: Actually, traditional herbal medicine may be overused in Korea. Expenditures of hospital cost & distrusts of scientific medicine are increasing gradually. So we surveyed the states of herbal medicine use according to home conditions among elementary school pupils. Materials and Methods: We interviewed pupils of three elementary schools in Gwangju with survey papers from 1st to 31th on May in 2007. We analyzed 905 returned surveys. Results: The number of pupils who have taken herbal medicines since birth was 590 (65.2 percent). The rate of herbal medicine use in male and in female was 68.9 percent, 62.0 percent and in apartment house and in western house was 72.9 percent, 60.3 percent, respectively. The rate of herbal medicine use in male and in apartment house was significant. The rate of herbal medicine use in above 1 million income was 68.8 percent and was higher significantly than in below 1 million income. There was no significant in the rate of herbal medicine use according to the religion of their parents. The rate herbal medicine use in graduated degree of their mother was 69.0 percent and was significant. The common reasons of herbal medicine use were looking weak without disease, for health promotion, frequent illnesses, orderly. Most of their parents thought about herbal medicine use positively (73.9 percent). Conclusion: The rate of herbal medicine use in elementary pupils was high. The rate of herbal medicine use was higher significantly in male, in apartment house, in above 1 million income & in graduated degree of mother. Their thoughts about herbal medicine use were positive, but may be a chance to distort western medicine.

BPMC와 Diazinon의 亞致死量이 벼멸구에 미치는 生物學的 影響

安龍濬,崔承允 서울大學校 農科大學 1980 서울대농학연구지 Vol.5 No.2

Some experiments were conducted to investigate the effects of the sublethal doses of BPMC(0-sec­Butylphenyl methyl carbamate) and diazinon (0, 0-Diethyl -0-(2-isopropyl-4-methyl-6-pyrimidinyl)-0-thionophosphate) on the biology of the brown planthopper (Nilaparvata lugens Stal) in the laboratory. One day old adults and 4th-instar nymphs were treated topically with various doses of BPMC and diazinon. The doses used were 70×10-⁴㎍, 10×10-⁴㎍ and 3×10-⁴㎍/insect for BPMC, and 400×10-⁴㎍, 100×10-⁴㎍ and 20×10-⁴㎍ / insect for diazinon. The lowest dose, giving no different adult mortality from the control, were defined as the sublethal dose in this experiment. The results obtained were as follows: 1. The insects treated with sublethal doses of the insecticides had a longer life span of the adults and produced more eggs. However, the higher doses caused decrease in longevity and in egg production. Those effects were greater in the nymphal treatments than in the adult treatments. 2. The peaks of the egg production were delayed with the increases of the doses in the nymphal treatment than in the adult treatment. 3. With the sublethal doses of the insecticides, treated females had mated to the treated males produced more eggs than any other mating combinations between the treated and untreated insects. 4. The obstruction of egg-chorion formation was observed with the insecticidal treatment and being severer with the higher doses. 5. The hatchabilities of the eggs produced by the treated insects were lower than those produced by the untreated ones. The reduction in the hatchability was the less with adult treatments than with the nymphal treatments. 6. There were no significant differences in the egg and nymphal periods with the treatment. The developmental periods of the insects were 26 days for the control, 27 days for BPMC, and 28 days for diazinon treatments.

조혈모세포이식 환자에서의 기계 환기의 위험 인자 : Assessment of Risk Factors

안중경,이홍기,황정혜,박세훈,이효락,송서영,이순일,박준오,김기현,김원석,정철원,임영혁,강원기,박근칠 대한조혈모세포이식학회 2002 대한조혈모세포이식학회지 Vol.7 No.1

연구배경: 조혈모세포이식을 시행한 환자에서 집중 치료 시 예후가 매우 나쁜 것으로 알려져 있고, 기계 환기는 강력한 사망 예측 인자로서 보고되고 있다. 그러나 현재까지 이식 환자에서 기계 환기의 위험 인자를 밝힌 연구는 매우 드물다. 따라서 기계 환기를 시행한 조혈모세포이식 환자의 임상적 특징을 살펴보고 기계 환기에 대한 위험 인자를 알아보고자 하였다. 방법: 삼성서울병원에서 조혈모세포이식을 시행한 환자 중 기계 환기를 시행한 23명과 기계 환기를 시행하지 않은 142명을 대상으로 후향적 연구를 시행하였다. 기계 환기에 대한 위험 인자의 여부에 관해서는 chi-square 또는 Fisher's exact 검정을 시행하였으며 기계 환기에 대한 각 위험 인자의 영향에 관해서는 다중로지스틱 회귀분석을 시행하였다. 결과: 기계 환기를 시행한 23명의 환자 중 30일째 생존자는 1명이었고 6개월째 생존율은 0%였다. 생존자와 사망자 모두에서 다기관 기능부전이 관찰되었으며, APACHE II 점수와 SAPS II 점수에 의한 예측 사망률은 각각 56%, 59%였다. 조혈모세포이식 후 기계 환기의 위험 인자로는 선행 질환이 혈액질환, 부분불일치 동종이식, 간정맥폐색성질환, 이식 전 질병 상태가 재발하였거나 약물에 반응하지 않는 경우였다. 다중로지스틱 회귀분석 결과 기계 환기의 위험 인자로 통계적으로 유의한 차이를 나타낸 것은 단지 부분불일치 동종이식을 시행한 경우였다. 결론: 현재까지 조혈모세포이식 환자에서 집중 치료의 역할에 대해서는 확실히 정립되어 있지는 않으며, 이식 환자에서 기계 환기는 강력한 사망 예측 인자이다. 따라서, 조혈모세포이식을 시행한 환자에서 기계 환기의 위험 인자와 불량한 예후 인자를 고려하여 기계 환기 여부에 대한 신중한 결정을 내려야 한다. Background: Respiratory failure requiring mechanical ventilation is a frequent, critical complication of hematopoietic stem cell transplantation (HSCT). Patients who require mechanical ventilatory support after HSCT generally have a very poor prognosis. Mechanical ventilation in HSCT recipients is a strong predictive factor of mortality. The objectives of this study are to describe clinical characteristics of HSCT recipients undergoing mechanical ventilation and to identify the risk factors for mechanical ventilatory support after HSCT. Methods: We performed a retrospective chart review of all patients >15 yrs old who received HSCT at Samsung Medical Center and subsequently required mechanical ventilatory support between 1996 and 2001. Results: Thirty-day mortality rate in HSCT recipients undergoing mechanical ventilation was 95.6%. The mean predictive mortality rates of APAHCE II score and SAPS II score were 56% and 59%, respectively. Reasons for mechanical ventila-tion were sepsis (47.8%) followed by fungal infection (13%) and diffuse alveolar hemorrhage (8.7%). Univariate analysis identified relapsed or refractory diseases at HSCT, hematologic disease, hepatic venoocclusive disease and allogeneic or HLA-mismatched transplant as significant risk factors for mechanical ventilation. On multivariate logistic regression analysis, only allogeneic mismatched transplant remained significant. Conclusion: Overall outcome of HSCT recipients undergoing mechanical ventilation is very poor. Therefore, the risk factors and the poor prognostic factors for mechanical ventilation should be taken into account in making further treatment decision for HSCT recipients requiring mechanical ventilation.

폐좌상시 폐단락률과 PEEP치료의 효과

김영식,황성오,최경훈,안무업,오중환,임경수,윤정환,강성준 大韓應急醫學會 1992 대한응급의학회지 Vol.3 No.1

To evaluate the physiologic extent of pulmonary contusion and effect of PEEP therapy for pulmonary contusion, we studied 16 patients received PEEP therapy with pulmonary contusion from nonpenetrating chest trauma. Hemodynamic parameters including pulmonary vascular resistance index and intrapulmonary shunt fraction were calculated from standard measurement, and arterial oxygen tension was measured. Pulmonary vascular resistance index and intrapulmonary shunt fraction were increased in patient group. Arterial oxygen tension was decreased with increase of the intrapulmonary shunt fraction(R=0.75). Arter minimal PEEP therap(5-10 ㎝H₂O), pulmonary vascular resistance index was remained unchanged and intrapulmonary shunt fraction was decreased without significant changes of pulmonary hemodynamics. Increment of arterial tension was increased with decrease of intrapulmonary shunt fraction(R=0.43). Decreased stroke volume index suggested of cardiac injury such as cardiac contusion in patient group. These results of our study suggested that increased intrapulmonary shunt fraction caused arterial hypoxia in pulmonary contusion and arterial oxygen tension was increased as a result of reduced intrapulmonary shunt by PEEP therapy.

고보자력의 Ba-Ferrite 제조

오영우,안영준 慶南大學校 附設 工業技術硏究所 1992 硏究論文集 Vol.10 No.-

Hot-rolled mill scale과 barium carbonate의 고상 반응에 의해 barium ferrite를 제조하였다. 측정한 자기 특정치는 보자력이 ??,, 잔류자속밀도가 ?? 그리고 최대 에너지적이 ??였으며, 공정상의 변수에 따른 결과를 제시하였다. Barium ferrite was made on a laboratory scale by the solid-state reaction of raw hot-rolled mill scale and barium carbonate. The coercivity Hc, remanence ?? and maximum energy product ?? are more than 1200Oe, 2100G and 0.9MG·Oe, respectively. The properties from processing parameters were investigated.

청소년의 식이행태 조사 : 서울·양평 두 지역간 비교 The Comparison of Urban and Rural Areas

최준호,안동현,최보율,강윤주,백영석,조연규,고복자,남정현 漢陽大學校 精神健康硏究 1998 精神健康硏究 Vol.17 No.-