• Title/Summary/Keyword: Quantification uncertainty

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Monitoring of Heavy Metals Migrated from Glassware, Ceramics, Enamelware, and Earthenware (유리제, 도자기제, 법랑 및 옹기류 재질의 식품용 기구 및 용기·포장의 중금속 이행량 모니터링)

  • Cho, Kyung Chul;Jo, Ye-Eun;Park, So-Yeon;Park, Yongchjun;Park, Se-Jong;Lee, Hye Young
    • Journal of Food Hygiene and Safety
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    • v.35 no.1
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    • pp.23-30
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    • 2020
  • This study investigated the migration levels of lead (Pb), cadmium (Cd), and arsenic (As) from food contact articles (glassware, ceramics, enamelware, and earthenware) into a food stimulant (4% v/v, acetic acid). Migration tests were performed at 25℃ for 24 h and all analyses were performed using Inductively-Coupled Plasma Mass Spectrometry (ICP-MS). The method was validated by linearity of calibration curves, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. In glassware, the migration concentrations ranged from not-detected (N.D.) to 752.21 ㎍/L and N.D. to 1.99 ㎍/L for Pb and Cd, respectively. In ceramics, the migration concentrations ranged from N.D. to 1,955.86 ㎍/L, N.D. to 74.06 ㎍/L, and N.D. to 302.40 ㎍/L for Pb, Cd, and As, respectively. In enamelware, the migration concentrations ranged from N.D. to 4.48 ㎍/L, N.D. to 7.00 ㎍/L, and N.D. to 52.00 ㎍/L for Pb, Cd, and Sb, respectively. In earthenware, the migration concentrations ranged from N.D. to 13.68 ㎍/L, N.D. to 0.04 ㎍/L, and N.D. to 6.71 ㎍/L for Pb, Cd, and As, respectively. All results were below the migration limits of Korea standards and specifications for food utensils, containers, and packages.

Effects of Motion Correction for Dynamic $[^{11}C]Raclopride$ Brain PET Data on the Evaluation of Endogenous Dopamine Release in Striatum (동적 $[^{11}C]Raclopride$ 뇌 PET의 움직임 보정이 선조체 내인성 도파민 유리 정량화에 미치는 영향)

  • Lee, Jae-Sung;Kim, Yu-Kyeong;Cho, Sang-Soo;Choe, Yearn-Seong;Kang, Eun-Joo;Lee, Dong-Soo;Chung, June-Key;Lee, Myung-Chul;Kim, Sang-Eun
    • The Korean Journal of Nuclear Medicine
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    • v.39 no.6
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    • pp.413-420
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    • 2005
  • Purpose: Neuroreceptor PET studies require 60-120 minutes to complete and head motion of the subject during the PET scan increases the uncertainty in measured activity. In this study, we investigated the effects of the data-driven head mutton correction on the evaluation of endogenous dopamine release (DAR) in the striatum during the motor task which might have caused significant head motion artifact. Materials and Methods: $[^{11}C]raclopride$ PET scans on 4 normal volunteers acquired with bolus plus constant infusion protocol were retrospectively analyzed. Following the 50 min resting period, the participants played a video game with a monetary reward for 40 min. Dynamic frames acquired during the equilibrium condition (pre-task: 30-50 min, task: 70-90 min, post-task: 110-120 min) were realigned to the first frame in pre-task condition. Intra-condition registrations between the frames were performed, and average image for each condition was created and registered to the pre-task image (inter-condition registration). Pre-task PET image was then co-registered to own MRI of each participant and transformation parameters were reapplied to the others. Volumes of interest (VOI) for dorsal putamen (PU) and caudate (CA), ventral striatum (VS), and cerebellum were defined on the MRI. Binding potential (BP) was measured and DAR was calculated as the percent change of BP during and after the task. SPM analyses on the BP parametric images were also performed to explore the regional difference in the effects of head motion on BP and DAR estimation. Results: Changes in position and orientation of the striatum during the PET scans were observed before the head motion correction. BP values at pre-task condition were not changed significantly after the intra-condition registration. However, the BP values during and after the task and DAR were significantly changed after the correction. SPM analysis also showed that the extent and significance of the BP differences were significantly changed by the head motion correction and such changes were prominent in periphery of the striatum. Conclusion: The results suggest that misalignment of MRI-based VOI and the striatum in PET images and incorrect DAR estimation due to the head motion during the PET activation study were significant, but could be remedied by the data-driven head motion correction.