• Title/Summary/Keyword: 전향적

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An Estimate of Image Quality and Radiation Doses of Coronary Artery in MDCT Using Prospective and Retrospective ECG Gating Scan Mode (MDCT 관상동맥 조영 검사에서 전향적 동조화 및 후향적 동조화 기법의 화질과 선량 관계)

  • Oh, Jong-Kap
    • Journal of radiological science and technology
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    • v.34 no.4
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    • pp.315-321
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    • 2011

  • The goal of this study is to reduce patient exposure dose by providing image quality and radiation dose according to inspection methods. Volume Computed Tomography Dose Index(CTDIvol) and Dose Length Product(DLP) of prospective and retrospective ECG gating snapshot segment of Coronary CT angiography(CTA) were measured each snapshot segment methods. CT number, noise, uniformity, and resolution were also measured using phantom under the same condition of coronary CTA. The results showed that CT number, noise, uniformity and resolution are similar to each other. In terms of CTDIvol and DLP, however, measurement dose of prospective ECG gating snapshot segment was lower than the retrospective case by 37.5% and 40.3%. Therefore, it is highly recommended that in the coronary CTA, prospective ECG gating scan mode should be chosen to reduce patient dose.

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Prospective Study on the Development of Glaucoma after Interferon alfa Therapy for Chronic Hepatitis B (만성 B형 간염 환자에서 인터페론 치료 후 녹내장 발생 여부의 전향적 연구)

  • Kwon, Young-Se;Choe, Yon-Ho;Hong, Sung-Bum
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.3 no.2
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    • pp.169-174
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    • 2000

  • Purpose: Previously reported ocular complications of interferon alfa administration are extremely rare. We experienced a 15-year-old boy with chronic hepatitis B who developed glaucoma after interferon alfa therapy. The purpose of this prospective study was to evaluate the possible development of glaucoma after interferon alfa therapy for chronic hepatitis B. Methods: Nine patients with chronic hepatitis B who visited Inha university hospital between February 1998 and July 1999 received interferon alfa therapy. We measured visual acuity, intraocular pressure, C/D ratio, and visual field examination at pre-interferon therapy, three and six months after therapy, respectively. Results: The total number of patients was 9 (4 boys and 5 girls). Mean age was $11.7{\pm}4.1$ years. The duration of therapy was 6 months and mean dosage of interferon was 5 million units. Compared with visual acuity, intraocular pressure, and C/D ratio at pre-therapy, those parameters at 3 months and 6 months after therapy showed no significant differences and none showed visual field defect after therapy. Conclusion: Our prospective study showed no evidence of development of glaucoma after interferon therapy. However, it is necessary to be concerned about the possibility of developing glaucoma or other ophthalmologic diseases after interferon therapy in chronic hepatitis B.

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An Analysis of Preservice Earth Science Teachers' Mental Models about Coriolis Force Concept (예비 지구과학 교사의 전향력 개념에 대한 정신모형 변화 분석)

  • Kim, Eunju;Lee, Hyundong;Lee, Hyonyong
    • Journal of The Korean Association For Science Education
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    • v.36 no.3
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    • pp.423-434
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    • 2016

  • The purpose of this study is to investigate preservice earth science teachers' mental models through applications of Coriolis force experiment apparatus. After the root of preconception was examined by face to face interviews based on the questionnaire, five preservice earth science teachers were finally selected for this study. The mental models about concept of Coriolis force was classified into naive mental model, static unstable mental model, dynamic unstable mental model, and scientific mental model through the result of individual interviews and their drawings. According to the mental model analysis about Coriolis' force conception, students C and M showed naive mental model about concept of Coriolis force before experiment. After the experiment, student M's model changed to static unstable mental model. Student C's model improved to dynamic unstable mental model. In adiition, students D and O's model improved from static unstable mental model to dynamic unstable mental model. In the case of student B, the dynamic unstable mental model was maintained after the experiment, however, student B's preconception changed to scientific concept. It turned out that a change occurred from low mental model level to integrated mental model after the application of the developed Coriolis' force experiment apparatus. According to the results, national curriculum is similar to static unstable mental model and the result of developed Coriolis' force experiment apparatus is similar to dynamic unstable mental model. It is suggested that it become the theoretical foundation to develop more comfortable and advanced Coriolis force experiment apparatus by improving the experiment apparatus.

  • https://doi.org/10.14697/jkase.2016.36.3.0423 인용 PDF KSCI