| 1 | Elucidate long-term changes of ozone in Shanghai based on an integrated machine learning method显示文摘Surface ozone(O_(3))is influenced by regional background and local photochemical formation under favorable meteorological conditions.Understanding the contribution of these factors to changes in O_(3)is crucial to address the issue of O_(3)pollution.In this study,we propose a novel integrated method that combines random forest,principal component analysis,and Shapley additive explanations to distinguish observed O_(3)into meteorologically affected ozone(O_(3_MET)),chemically formed from local emissions(O_(3_LC)),and regional background ozone(O_(3_RBG)).Applied to three typical stations in Shanghai during the warm season from 2013 to 2021,the results indicate that O_(3_RBG)in Shanghai was 48.8±0.3 ppb,accounting for 79.6%–89.4%at different sites,with an overall declining trend of 0.018 ppb/yr.O_(3_LC)at urban and regional sites ranged from 5.9–9.0 ppb and 8.9–14.6 ppb,respectively,which were significantly higher than the contributions of 2.5–7.4 ppb at an upwind background site.O_(3_MET)can be categorized into those affecting O_(3)photochemical generation and those changing O_(3)dispersion conditions,with absolute contributions to O_(3)ranging from 13.4–19.0 ppb and 13.1–13.7 ppb,respectively.We found that the O_(3)rebound in 2017,compared to 2013,was primarily influenced by unfavorable O_(3)dispersion conditions and unbalanced emission reductions;while the O_(3)decline in 2021,compared to 2017,was primarily influenced by overall favorable meteorological conditions and further emissions reduction.These findings highlight the challenge of understanding O_(3)change due to meteorology and regional background,emphasizing the need for systematic interpretation of the different components of O_(3). | Jin Xue Fangting Wang Kun Zhang Hehe Zhai Dan Jin Yusen Duan Elly Yaluk Yangjun Wang Ling Huang Yuewu Li Thomas Lei Qingyan Fu Joshua S.Fu Li Li | 2023 | Frontiers of Environmental Science & Engineering2023，17，11： | 0 |
| 2 | Experimental Study of 103Pd Stent Affecting Dynamic Equilibrium Between Proliferation and Apoptosis of Vascular Smooth Muscle Cells显示文摘Objectives By observing γ ra-dioactive 103Pd stent affecting the proliferation and apoptosis of vascular smooth muscle cells (VSMCs) to explore the mechanism of radioactive stent preventing in-stent restenosis. Methods Fifty male New Zealand rabbits were randomized into stent group and 103Pd stent group. Control group was set up. The materials were harvested on 3, 7, 14, 28, 56 days after operation and the following investigations were carried out, including pathomorphology, immunohistochemi-stry, apoptosis (TUNEL) and in situs hybridization studies. Results ①The severity of the stenosis in 103Pd stent group was less than that of stent group. It was the most obvious on 56th day (P < 0.01). ②The expression of PCNA of 103Pd stent group was lower than that of stent group on 3 to 28 days. It was the most obvious on 7th day, 16.35%±0.79% vs 24.36%±0.55% (P < 0.01). ③TUNEL method showed that the 103Pd stent group had much more apoptosis of VSMCs than that of stent group. The highest rate of apoptosis appeared on day 7, 14.72%±0.53% vs 12.42%±1.13% (P < 0.01). ④ By calculating the ratio of PCNA/apoptosis (P ∶ A), a much lower ratio was seen in 103Pd-stent group than that of stent group at 3 to 28 days. There was significant statistic difference between two groups(P < 0.05). ⑤For bcl-2/bax ratio, the result in 103Pd-stent group was lower than that of stent group at 3 to 28 days. It had significant statistic difference (P < 0.05). Conclusions γ radi-oactive stent can inhibit the proliferation and accelerate apoptosis of injured media VSMCs. Also it can de-crease the ratio of proliferation to apoptosis and relieve the severity of restenosis. | Liu Yingmei Fu Yuewu Wei Yulin Wu Wei | 2006 | South China Journal of Cardiology2006，7，2： | 0 |
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