• The Korean Journal of Nuclear Medicine
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• 제38권1호
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• pp.21-29
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• 2004

Purpose: Much evidence suggests long-term cigarette smoking alters coronary vascular endothelial response. On this study, we applied nonnegative matrix factorization (NMF), an unsupervised learning algorithm, to CO-less $H_2^{15}O-PET$ to investigate coronary endothelial dysfunction caused by smoking noninvasively. Materials and methods: This study enrolled eighteen young male volunteers consisting of 9 smokers $(23.8{\pm}1.1\;yr;\;6.5{\pm}2.5$ pack-years) and 9 nonsmokers $(23.8{\pm}2.9 yr)$. They do not have any cardiovascular risk factor or disease history. Myocardial $H_2^{15}O-PET$ was performed at rest, during cold ($5^{\circ}C$) pressor stimulation and during adenosine infusion. Left ventricular blood pool and myocardium were segmented on dynamic PET data by NMF method. Myocardial blood flow (MBF) was calculated from input and tissue functions by a single compartmental model with correction of partial volume and spillover effects. Results: There were no significant difference in resting MBF between the two groups (Smokers: 1.43 0.41 ml/g/min and non-smokers: $1.37{\pm}0.41$ ml/g/min p=NS). during cold pressor stimulation, MBF in smokers was significantly lower than 4hat in non-smokers ($1.25{\pm}0.34$ ml/g/min vs $1.59{\pm}0.29$ ml/gmin; p=0.019). The difference in the ratio of cold pressor MBF to resting MBF between the two groups was also significant (p=0.024; $90{\pm}24%$ in smokers and $122{\pm}28%$ in non-smokers.). During adenosine infusion, however, hyperemic MBF did not differ significantly between smokers and non-smokers ($5.81{\pm}1.99$ ml/g/min vs $5.11{\pm}1.31$ ml/g/min ; p=NS). Conclusion: in smokers, MBF during cold pressor stimulation was significantly lower compared wi4h nonsmokers, reflecting smoking-Induced endothelial dysfunction. However, there was no significant difference in MBF during adenosine-induced hyperemia between the two groups.

• Land and Housing Review
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• 제13권2호
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• pp.49-64
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• 2022

To effectively lead "Innovative City Season 2", it is important to investigate whether the creation of an innovative city has a positive effect on the revitalization of the hinterland town economy. This study explores the effects (external effects) of increases in the number of workers at public institutions in the innovative city of Jeollabuk-do, located closest to the hinterland town (Jeonju-si). In the results, we show that increases in the number of workers positively affected the commercial real estate market, which is one of the barometers that show the revitalization level. On the other hand, the effect was found to be limited to the new downtown commercial real estate market with good accessibility and modernized facilities and services. This suggests that the innovative city adjacent to the hinterland town meets the purpose of the innovative city to some extent by generating a positive external effect, especially in accessible and modernized areas. To further expand the positive spillover effects of an innovative city on the hinterland town, it is necessary to expand public institutions for relocation, improve settlement conditions, and establish a practical cooperation system between specialized public institutions and hinterland-related industries.