${H_2}^{15}O$ PET을 이용한 뇌혈류 파라메트릭 영상 구성을 위한 알고리즘 비교

이재성,이동수,박광석,정준기,이명철,Lee, Jae-Sung,Lee, Dong-Soo,Park, Kwang-Suk,Chung, June-Key,Lee, Myung-Chul 대한핵의학회 2003 핵의학 분자영상 Vol.37 No.5

목적: ${H_2}^{15}O$ PET의 정량화를 위하여 1-조직 구획모델이 쓰이며, 뇌혈류와 조직/혈액 분배계수를 구하기 위하여 nonlinear least squares (NLS) 방법이 사용되나 계산 시간이 긴 등의 문제로 파라미터를 각화소마다 구해야 하는 파라메트릭 영상 구성에는 적합하지 않다. 이 연구에서는 이와 같은 NLS 문제점을 극복하여 파라메트릭 영상을 빠르게 구성하기 위하여 제안된 파라미터 추정 알고리즘들을 구현하고, 이 방법들의 통계적 신뢰도와 계산의 효율성을 비교하였다. 대상 및 방법: 이 연구에서 이용한 방법들은 linear least squares (LLS), linear weighted least squares (LWLS), linear generalized least squares (GLS), linear generalized weighted least squares (GWLS), weighted integration (WI), 그리고 model-based clustering method (CAKS)이다. 노이즈 정도에 따른 각 파라메트릭 영상법의 정확성 및 통계적 신뢰성을 알아보기 위하여 Zubal 뇌모형(brain phantom)으로부터 동적 PET 영상을 모사하고 포아송노이즈를 더한 후 각 파라메트릭 영상 구성 방법을 적용하였다. 또한 정상인 16명에 대하여 얻은 실제 자료에 대하여 이 방법들을 적용하고 결과를 비교하였다. 결과: 뇌혈류와 분배계수에 대한 평균 오차는 방법에 따라 크게 다르지 않았으며 모든 방법이 뇌혈류 및 분배계수 추정에 있어 무시할 만한 바이어스를 보였다. 파라메트릭 영상의 정성적 특성 또한 유사하였으나 CAKS 방법의 계산 속도가 월등하여 NLS 방법의 약 1/500, LLS 방법의 약 1/25의 계산시간을 보였다. 결론: 뇌혈류 파라메트릭 영상 구성을 위한 빠른 파라미터 추정 알고리즘들 중에 보다 개선되어 제안된 LWS, GLS, GLWS, CAKS 방법들이 단순하고 빠른 LLS, WI 방법들에 비하여 통계적 신뢰성을 크게 향상시키지는 못하나 CAKS 방법은 계산 시간을 유의하게 단축시키므로 가장 적합한 파라메트릭 영상 구성방법이라 할 수 있을 것이다. Purpose: To obtain regional blood flow and tissue-blood partition coefficient with time-activity curves from ${H_2}^{15}O$ PET, fitting of some parameters in the Kety model is conventionally accomplished by nonlinear least squares (NLS) analysis. However, NLS requires considerable compuation time then is impractical for pixel-by-pixel analysis to generate parametric images of these parameters. In this study, we investigated several fast parameter estimation methods for the parametric image generation and compared their statistical reliability and computational efficiency. Materials and Methods: These methods included linear least squres (LLS), linear weighted least squares (LWLS), linear generalized least squares (GLS), linear generalized weighted least squares (GWLS), weighted Integration (WI), and model-based clustering method (CAKS). ${H_2}^{15}O$ dynamic brain PET with Poisson noise component was simulated using numerical Zubal brain phantom. Error and bias in the estimation of rCBF and partition coefficient, and computation time in various noise environments was estimated and compared. In audition, parametric images from ${H_2}^{15}O$ dynamic brain PET data peformed on 16 healthy volunteers under various physiological conditions was compared to examine the utility of these methods for real human data. Results: These fast algorithms produced parametric images with similar image qualify and statistical reliability. When CAKS and LLS methods were used combinedly, computation time was significantly reduced and less than 30 seconds for $128{\times}128{\times}46$ images on Pentium III processor. Conclusion: Parametric images of rCBF and partition coefficient with good statistical properties can be generated with short computation time which is acceptable in clinical situation.

Physiological Concentrations of Trans-11 18:1 Vaccenic Acid Suppress Pro-inflammatory Markers under Acute Inflammation in Isolated ICR Mice Splenocytes

이재성,임지나,Tao Wang,Sang-Bum Lee,황진희,U-Suk Jung,Min-Jeong Kim,최성호,Satoshi Ishizuka,이홍구 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1

Direct influences of dietary trans-11 18:1 vaccenic acid (TVA) at physiological concentrations of 50-200 μM were evaluated for cell growth, cytotoxic activity, and cytokine production in leukocytes isolated from the mouse spleen. TVA supplementation for 24 h induced growth of splenocytes at concentrations of 50-200 μM, except for 100 μM. The cytokines TNFα, IFNγ, and IL-10 of splenocytes were stimulated by 100 μM TVA. Induced production of TNFα in splenocytes challenged with lipopolisaccharides was suppressed by 100 μM TVA. Physiological levels of TVA had direct effects on growth and cytokine production in splenocytes. Further in vivo studies are needed to improve understanding of the precise influence of trans fatty acids on production of pro-inflammatory markers under acute inflammation conditions.

국제협력을 통한 원자력 민감기술 확보방안에 관한 연구

이재성,박승기,최영명,Lee Jae-Seong,Park Seung-Gi,Choe Yeong-Myeong 한국국방경영분석학회 1990 한국국방경영분석학회지 Vol.16 No.2

The objective of this study is to propose how to acquire through international cooperation the sensitive nuclear technology, so called reprocessing technology. In spite of the need to reuse spent fuel, the transfer of the sensitive technology has been tightly controlled by the nuclear advanced countries due to the fear of nuclear proliferation and, in fact, it would be impossible to secure it by the economic means. In this regard, as a means of acquiring the sensitive nuclear technology, this study proposes the following; 1) President's declaration concerning the peaceful uses of nuclear energy, 2) the establishment and maintenance of national basis through inter-ministerial cooperation, 3) as a confidence building measure, the efforts to strengthen our role in the international nuclear community, and 4) the establishment of the synthetic feedback system to efficiently coordinate. In line with those stated above, this study suggests that it be necessary to invest consistently for developing new technologies and cultivating human resources. Furthermore, this study proposes the necessity to resolve the problems lying ahead by the national consensus achieved through the discussions among the public concerning the sensitive nuclear technology.

연구체제에 큰 변혁 목적지향적 연구필요

이재성,Lee, Jae-Seong 한국과학기술단체총연합회 1980 과학과 기술 Vol.13 No.12

6월 밤하늘에 혜성 2개 뜬다

이재성,Lee, Jae-Seong 한국과학기술단체총연합회 2004 과학과 기술 Vol.37 No.6

해상 어류가두리양식장의 환경영향 평가: II. 가두리 양식장 퇴적물의 산소-황화수소 경계면에서 황화수소의 산화율 및 무산소 퇴적층에서 황산염 환원율 추정

이재성,김기현,유준,이필용,정래홍,이원찬,한정희,이용화,Lee, Jae-Seong,Kim, Kee-Hyun,Yu, Jun,Lee, Pil-Yong,Jung, Rae-Hong,Lee, Wong-Chan,Han, Jung-Jee,Lee, Yong-Hwa 한국해양학회 2004 바다 Vol.9 No.2

We measured the vertical profiles of $O_2$, H$_2$S, and pH in sediment pore water beneath marine cage fish farms using a microsensor with a 25 ${\mu}{\textrm}{m}$ sensor tip size. The sediments are characterized by high organic material load. The oxygen consumption, hydrogen sulfide oxidation, and sulfate reduction rates in the microzonations (derived from the vertical distribution of chemical species concentration) were estimated by adapting a simple one-dimensional diffusion-reaction model. The oxygen penetration depth was 0.75 mm. The oxic microzonations were divided into upper and lower layers. Due to hydrogen sulfide oxidation within the oxic zone, the oxygen consumption rate was higher in the lower layer. The total oxygen consumption rate integrated with reaction zone depth was estimated to be 0.092 $\mu$mol $O_2$cm$^{-2}$ hr$^{-1}$ . The total hydrogen sulfide oxidation rate occurring within 0.7 mm thickness was estimated to be 0.030 $\mu$mo1 H$_2$S cm$^{-2}$ hr$^{-1}$ , and its turnover time in the oxic sediment layer was estimated to be about 2 minutes. This suggests that hydrogen sulfide was oxidized by both chemical and microbial processes in this zone. The molar consumption ratio, calculated to be 0.84, indicates that either other electron accepters exit on hydrogen sulfide oxidation, or elemental sulfur precipitation occurs near the $O_2$- H$_2$S interface. Total sulfate reduction flux was estimated to be 0.029 $\mu$mol cm$^{-2}$ hr$^{-1}$ , which accounted for more than 60% of total $O_2$ consumption flux. This result implied that the degradation of organic matter in the anoxic layer was larger than in the oxic layer. 유기물이 많이 유입되는 해상어류가두리 양식장 퇴적물에서 전극 크기가 25$mu extrm{m}$인 미세전극을 이용하여 공극수의 산소, 황화수소, pH의 미세연직 농도를 측정하였다. 산소와 황화수소의 연직분포에서 얻어진 미세구간에 1차 확산ㆍ반응모델을 적용하여 각 구간에서의 산소 소모율, 황화수소 산화율, 황산염의 환원율을 추정하였다. 산소투과깊이는 0.75 mm였으며, 미세구간은 상부와 하부층 2개로 나누어졌다. 산소소모는 황화수소의 산화 영향으로 상부층에 비해 하부층에서 높았고 총산소소모플럭스는 0.092 $\mu$mol $O_2$$cm^{-2}$ $hr^{-1}$였다. 산화층에서 황화수소 산화는 0.7 mm 두께에서 0.030$\mu$mo1 H$_2$S $cm^{-2}$ $hr^{-1}$의 결과를 나타냈으며, 이 곳에서 황화수소의 turnover time은 약 2분으로 화학적 산화와 생물학적 산화가 동시에 일어나고 있었다. 황화수소와 산소의 소모율 비는 0.84로 황화수소 산화에 산소 이외의 다른 전자수용체가 사용되거나 산소-황화수소 경계면 주변에서 황 침전의 가능성을 시사하고 있었다. 추정된 총 황산염 환원 플럭스는 0.029$\mu$mol $cm^{-2}$ $hr^{-1}$로서 총산소소모플럭스의 60% 이상을 차지하고 있어 무산소 환경에서 유기물 분해가 산화환경에서보다 큰 역할을 하는 것으로 나타났다.

은밀하게 날아 벌같이 쏜다

이재성,Lee, Jae-Seong 한국과학기술단체총연합회 2003 과학과 기술 Vol.36 No.4

Manufacturing Techniques of Ancient Forged High-tin Bronze Wares from Archaeological Sites in Bagan, Myanmar

이재성,Yee Yee Win,Jae Eun Yu,Bonnie Lee 한국문화재보존과학회 2023 보존과학회지 Vol.39 No.5

Bronze wares made with forged high-tin bronze technology were first produced in thePersian region of the Orient, gradually brought to India and then to China and the Korean Peninsula. By scientifically analyzing bronze artifacts of Myanmar, which is located halfway between Persiaand Korea, it is possible to confirm the trade and the propagation route of technology at the time. This study scientifically analyzed bronze artifacts excavated from the Bagan ruins in Myanmar toidentify the manufacturing technology. Forged high-tin bronze wares in Bagan Dynasty are with alloycompositions Cu-Sn. Composed of Cu-Sn only were manufactured by alloying Cu with Sn in a ratioof 76 wt% and 24 wt%, which is a relatively high tin content. High-tin bronze wares composedof Cu-Sn were manufactured with the bronze material of an alloy of Cu and a large amount of Snby hot working (forging) and finished by quenching. The microstructure indicates temperatures atwhich the quenching was performed and various microstructures that occur in different temperatureranges are observed such as β (M), γ phase, δ phase as well as primary crystals, α phase. Thepresence of different microstrucures suggests multiple high-tin bronze wares were quenched at a widerange of temperatures. The non-metallic inclusions of the bronze wares contain sulfur, which indicateswith high possibility that the copper provided as the raw material was extracted from copper orescontaining sulfur.

대학에서 본 신기술개발과 육성책

이재성,Lee, Jae-Seong 한국과학기술단체총연합회 1980 과학과 기술 Vol.13 No.5

전자부품 및 소재공업을 위한 소재기술의 발전

이재성,Lee, Jae-Seong 한국전자정보통신산업진흥회 1984 電子振興 Vol.4 No.9