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과학 문제해결 과정을 활용한 초등 과학 수행평가 도구의 개발과 적용
최회정,임채성,김은진 부산교육대학교 과학교육연구소 2003 科學敎育硏究 Vol.28 No.-
In this study, the performance assessment tools using processes of solving problems in science were developed and applied to instruction, then their effects were analyzed both quantitatively and qualitatively. The results of the research can be summarized as follows: First, among the performance assessment tools developed in the study, the students' response formats were shown to be a useful method to understand collectively the processes and products of learning, and the students' appreciation toward it was also found to be positive. Second, in science instruction which proceeded through each step of science problem solving the science attitudes of the experimental group, although not statistically significant, showed more improvement than comparison one. Among the categories of science attitudes, 'attitudes toward science subject and the unit or topic studied' showed statistically significant improvement, which is interpreted as results of making harmony of preexisting students' interests with difficulty levels of tasks. Third, for overall several science process skills, there were no significant improvement. However, the subskills of inferring, data interpretation, and drawing conclusion were found to be increased significantly, which might be due to the frequency and depth of use of these skills in real instruction. Fourth, for aspect of the understanding of science knowledge and applying of it, there were statistically significant increase. That is, it was interpreted, through active participation in learning task across the whole range of performance of problem solving, that the abilities to applying science knowledge to the given problems were significantly increased.
티타늄의 NaOH 수용액 침적 및 열처리가 유사체액 중에서의 인산칼슘 석출에 미치는 영향
최진용,정회웅,이민호,배태성 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4
This study was performed to examine whether the precipitation of calcium phosphate on titanium surface is affected by the immersion in NaOH solution and heat treatment. Titanium plates of 10×10×1㎜ in dimensions were polished sequentially from #240 to #2,000 emery paper and one surface of each specimen was received an additional polishing sequence through 0.1㎛ alumina paste. Polished specimens were soaked in 1, 3, 6, 10M-NaOH aqueous solutions at 60℃ for 24 hrs, and 6M-NaOH-treated group were heated to 400, 600, 800℃ for 1 h. After the alkali treatment in the NaOH aqueous solution and heat treatment, specimens were soaked in the Hanks solution with pH 7.4 at 36.5℃ for 7 days in the NaOH-treated groups and for 30 days in the NaOH and heat-treated groups. The results obtained were summarized as follows; 1. The precipitation of calcium phosphate on titanium was accelerated by the immersion in NaOH solution and heat treatment. 2. The precipitation of calcium phosphate was densified with the increase of molar ratio of NaOH. 3. The heat-treated titanium surface at 600℃ showed the precipitation of dense and fine apatite crystals.
강봉의 냉간 인발시 발생하는 잔류응력 성분에 관한 유한요소 해석
백태현,최희진 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-
Prediction the behaviour of steel during a deformation process under service conditions is one of the main challenges in cold forming, The design of optimized forging schedules, by means of conventional trial and error methods, has become increasingly heavy in terms of time and cost in a competitive environment. During the last few years, numerical simulations have become a very efficient tool to arrive these goals. In this paper, finite element analysis was used to analyze the distribution of residual stress components in a rod with respect die angle and/or area reduction in cold drawing process. Cold drawing brought sunken-in deformation at the bottom land of the rod that was in accord with the result obtained from the analysis using ABAQUS. The results obtained from finite element analysis were in close agreement with the determined high-accuracy measurements.
SW1353 인간 연골세포에서 산화적 스트레스에 대한 schisandrin A의 세포 보호 효과
정진우(Jin-Woo Jeong),최은옥(Eun Ok Choi),권다혜(Da Hye Kwon),김범회(Bum Hoi Kim),박동일(Dong Il Park),황혜진(Hye Jin Hwang),김병우(Byung Woo Kim),최영현(Yung Hyun Choi) 한국생명과학회 2017 생명과학회지 Vol.27 No.9
활성산소종으로 유도되는 연골 세포의 apoptosis는 퇴행성 관절염의 발병 기전에 중요한 역할을 한다. Schisandrin 속의 과일에서 발견되는 생체 활성 화합물인 schisandrin A는 여러 가지 약리학적 작용을 하는 것으로 보고 되고 있다. 현재까지 schisandrin A의 유도체들의 항산화 효과에 대해서는 여러 연구가 보고되었지만, schisandrin A의 항산화 효능의 분자 기전은 아직 미해결 상태로 남아 있다. 본 연구는 SW1353 인간 연골세포에서 산화적 스트레스(H2O2)에 대한 schisandrin A의 세포 보호 여부를 조사하였다. 본 연구의 결과에 의하면 schisandrin A는 PARP 단백질의 분해와 caspase-3의 활성 차단을 통해 H2O2에 의해 유도된 성장 억제와 apoptosis를 유의적으로 억제하였다. 이러한 schisandrin A의 anti-apoptotic 효과는 미토콘드리아 기능 손상의 억제와 pro-apoptotic Bax의 발현 증가 및 anti-apoptotic Bcl-2의 발현 감소의 차단과도 관련이 있었다. 또한, schisandrin A는 ROS의 생성과 DNA 손상 마커인 H2AX의 인산화도 효과적으로 저해하였다. 따라서 SW1353 연골세포에서 schisandrin A는 산화적 스트레스에 의한 ROS 생성의 억제를 통하여 apoptosis와 DNA 손상을 보호하였음을 알 수 있었다. 결론적으로 본 연구의 결과는 schisandrin A가 ROS의 과잉 생산으로 인한 산화적 장애에 치료적 잠재력이 있음을 보여준다. Chondrocyte apoptosis induced by reactive oxygen species (ROS) plays an important role in the pathogenesis of osteoarthritis. Schisandrin A, a bioactive compound found in fruits of the Schisandra genus, has been reported to possess multiple pharmacological and therapeutic properties. Although several studies have described the antioxidant effects of analogues of schisandrin A, the underlying molecular mechanisms of this bioactive compound remain largely unresolved. The present study investigated the cytoprotective effect of schisandrin A against oxidative stress (hydrogen peroxide[H2O2]) in SW1353 human chondrocyte cells. The results showed that schisandrin A preconditioning significantly inhibited H2O2-induced growth inhibition and apoptotic cell death by blocking the degradation of poly (ADP-ribose) polymerase proteins and down-regulating pro-caspase-3. These antiapoptotic effects of schisandrin A were associated with attenuation of mitochondrial dysfunction and normalization of expression changes of proapoptotic Bax and antiapoptotic Bcl-2 in H2O2-stimulated SW1353 chondrocytes. Furthermore, schisandrin A effectively abrogated H2O2-induced intracellular ROS accumulation and phosphorylation of histone H2AX at serine 139, a widely used marker of DNA damage. Thus, the present study demonstrates that schisandrin A provides protection against H2O2-induced apoptosis and DNA damage in SW1353 chondrocytes, possibly by prevention of ROS generation. Collectively, our data indicate that schisandrin A has therapeutic potential in the treatment of oxidative disorders caused by overproduction of ROS.
최진학 ( Jin Hak Choi ),김광회 ( Kwang Hoi Kim ),이대진 ( Dae Jin Lee ),신이철 ( Lee Cheol Shin ),김철수 ( Chul Soo Kim ),서성모 ( Sung Mo Su ) 대한내과학회 1973 대한내과학회지 Vol.16 No.10
The authors estimated the serum uric acid of 95 hypertensive patients who were admitted in hanil Hospital and compared with that of 51 normal persons. The change of serum uric acid after oral administration of various antihypertensive drugs such as chlorth
증례 : 원발성 간암에서 발생한 이차성 다혈구혈증 1 예 보고
최진학 ( Jin Hak Choi ),김광회 ( Kwang Hoi Kim ),이대진 ( Dae Jin Lee ),김택춘 ( Takik Choon Kim ),김철수 ( Chul Soo Kim ),서성모 ( Sung Mo Su ) 대한내과학회 1973 대한내과학회지 Vol.16 No.5
A case of secondary polycythemia associated with primary hepatoma was presented, and clinicoetiological aspects were briefly reviewed. The diagnosis of hepatoma was established with the findings of hard and irregular surface of a enlarged huge liver and in