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This study analyzes the impact of circulation types (CTs) on ozone (O 3 ) pollution in Beijing. The easterly high-pressure (SWW) circulation occurred most frequently (30%; 276 day), followed by northwesterly high-pressure (AN) circulation (24.3%; 224 day). The SWW type had the highest O 3 anomaly of +17.28 µg/m 3 , which was caused by excellent photochemical reactions, poor diffusion ability and regional transport. Due to the higher humidity and precipitation in the low-pressure type (C), the O 3 increase (+8.02 µg/m 3 ) was less than that in the SWW type. Good diffusion/wet deposition and weak formation ability contributed to O 3 decrease in AN (-12.54 µg/m 3 ) and northerly high-pressure (ESN) CTs (-12.26 µg/m 3 ). The intra-area transport of O 3 was significant in polluted circulations (SWW- and C-CTs). In addition, higher temperature, radiation and less rainfall also contributed to higher O 3 in northern Beijing under the SWW type. For the clean CTs (AN and ESN CTs), precursor amount and intra-area transport played a dominant role in O 3 distribution. Under the northeasterly low-pressure CT, better formation conditions and higher precursor amount combined with the intra-area southerly transport to cause higher O 3 values in the south than in the north. The higher O 3 in the northwestern area under the northeasterly high-pressure type was influenced by weaker titration loss and high O 3 concentration in previous day. Annual variation in the CTs contributed up to 86.1% of the annual variation in O 3 . About 78%-83% of the diurnal variation in O 3 resulted from local meteorological factors., (Copyright © 2022. Published by Elsevier B.V.)

Carbon monoxide (CO) is primarily the result of incomplete combustion, which has important impacts on the atmospheric chemical cycle and climate. Improved quantitative characterization of long-term CO trends is important for both atmospheric modeling and the design and implementation of policies to efficiently control multiple pollutants. Due to the limitations of high time-resolution and high-quality long-term observational data, studies on long-term trends in the CO concentration in China are quite limited. In this study, the observational data of the concentration of CO in a rural site of Beijing during 2006-2018 was used to analyze the long-term trend in CO concentration in Beijing. The Theil-Sen method and the generalized additive model (GAM)-based method, were used to conduct the trend estimation analysis. We found that the concentration of CO at the Shangdianzi site showed a significant downward trend during 2006-2018, with a decline rate of 22.8 ± 5.1 ppbV per year. The declining trend in CO also showed phasic characteristics, with a fast decreasing rate during the period of 2006-2008, stable variations during the period of 2009-2013 and a continuous downward trend after 2013. The declining trend in the CO concentration in the south to west (S-W) sectors where the polluted air masses come from is more rapid than that in the sectors where the clean air masses come from. The declining trend in the CO concentration implies the improved combustion efficiency and the successful air pollution control policies in Beijing and the surrounding area., (Copyright © 2020. Published by Elsevier B.V.)

Objectives: To determine the relationship between depressive symptoms and progression of carotid intima-media thickness (cIMT) in a Beijing community-based population., Design: Prospective cohort study between 2014 and 2018., Setting: Dwellers without cardiovascular disease, hypertension or diabetes from a Beijing community., Participants: 3849 Chinese community-dwelling individuals who underwent baseline screening for depressive symptoms were invited to participate in the study in 2014 and follow-up visit in 2018. Among them, 2124 participants completed carotid ultrasound examination both at baseline and a follow-up visit. After further excluding patients with a history of stroke, myocardial infarction or lower extremity arterial stenosis and those with a diagnosis of hypertension or diabetes and ankle-brachial index ≤0.9 at baseline, 1011 eligible participants were finally included., Primary Outcome Measure: The rate of mean cIMT change., Results: Over a median follow-up period of 4.40 years, the overall rate of mean cIMT change was 2.23% (-5.64% to 9.51%). After adjustment for 13 covariates, there was an increase of 2.36% (β=2.36, 95% CI: 0.37 to 4.36, p=0.020) for the rates of mean cIMT change in the depressive group compared with the control group. Furthermore, this association was modified by drinking status (β=3.22, 95% CI: 1.25 to 5.19, P-interaction=0.006)., Conclusion: Depressive symptoms were independently associated with progression of mean cIMT in a community-based cohort in Beijing, China. Furthermore, this relationship was modified by drinking status., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Ozone pollution has recently become a severe air quality issue in the Beijing-Tianjin-Hebei region. Due to the lack of a precursor emission inventory and complexity of physical and chemical mechanism of ozone generation, numerical modeling still exhibits significant deviations in ozone forecasting. Owing to its simplicity and low calculation costs, the time series analysis model can be effectively applied for ozone pollution forecasting. We conducted a time series analysis of ozone concentration at Shangdianzi, Baoding, and Tianjin sites. Both seasonal and dynamic ARIMA models were established to perform mid- and long-term ozone forecasting. The correlation coefficient R between the predicted and observed value can reach 0.951, and the RMSE is only 10.2 μg·m -3 for the monthly average ozone prediction by the seasonal ARIMA model. The correlation coefficient R between the predicted and observed value increased from 0.296-0.455 to 0.670-0.748, and RMSE was effectively reduced for the 8-hour ozone average predicted by the dynamic ARIMA model.

Objective: To investigate the influence of the preoperative factors on the segmental range of motion (ROM) during long-term follow-up after artificial cervical disc replacement (ACDR), so as to further improve the selection of surgical indications for ACDR. Methods: Retrospective analysis was performed on 71 patients with cervical degenerative diseases who underwent single-segment Bryan ACDR in Beijing Jishuitan Hosptial from December 2003 to December 2008, and a 10-year clinical follow-up was conducted. Among the patients, 44 were males and 27 were females, with a mean age of (45±8) years at operation. The mean follow-up time was (129±14) months. Preoperative and follow-up imaging evaluation including measurement of the segmental range of motion (ROM) by cervical X-ray, and preoperative height of intervertebral space was measured by cervical lateral X-ray. According to CT and coronal reconstruction, the grade of paravertebral ossification (PO) was assessed. Clinical symptoms assessment including the Japanese Orthopaedic Association scoring (JOA), the Neck Disability Index (NDI) evaluation was performed preoperatively. Multivariate logistic regression analysis was used to analyze the influencing factors of the range of motion of the surgical segment during follow-up. The best cut-off value was calculated by receiver operating characteristic (ROC) curve. Results: The preoperative and follow-up ROM at the operated segment was 9.7°±4.5° and 8.7°±5.4°, respectively ( P >0.05). Univariate analysis revealed that the postoperative segmental ROM was not significantly correlated with the factors including the surgical level, gender, age, and preoperative clinical diagnosis (1: Radiculopathy; 2: Myelopathy; 3: Mixed type), preoperative segmental ROM, preoperative JOA score and preoperative NDI score (all P >0.05), and was significantly correlated with imaging diagnosis (1: cervical disc herniation; 2: degenerative cervical stenosis), preoperative PO grade (both P <0.05). The multi-factor analysis showed that preoperative segmental ROM ( OR =1.228, 95% CI :1.012-1.489, P <0.05) and PO grade ( OR =0.190, 95% CI : 0.085-0.424, P <0.05) had significance in the overall test, but imaging diagnosis had no significance in the overall test ( P >0.05). The optimal cutoff value of preoperative segmental ROM and PO grade was 9.185° and grade 2.5 assessed by ROC curve, and the area under the ROC curve was 0.86 and 0.72, respectively. Conclusions: ACDR surgery can achieve satisfactory long-term effects for patients with nerve root type, spinal cord type and mixed type cervical degenerative diseases, and effectively retain the overall ROM of the cervical spine and the ROM of replacement segments. Patients with good preoperative segmental ROM and lower PO levels have a greater chance of obtaining good segmental ROM in the long-term postoperatively.

Background: Unequal allocation of medical physician resource represents one of major problems in the current medical service management in China and many other countries. This study is designed to analyze the current distribution of physicians in 31 provincial administrative regions in China, to estimate the fairness of the distribution of physicians and provide a theoretical basis for the improvement of the allocation of physicians., Methods: This study took physicians from 31 provincial administrative regions in China as the study objects, and the data were obtained from the China Health Statistics Yearbook 2019 and the official website of the National Bureau of Statistics of China. Calculation of the Gini coefficient (G) and the Theil index (T) were carried out by drawing the Lorenz curve. The fairness of present physician location in 31 provincial administrative regions in China was analyzed from the perspective of distribution by both population and service area., Results: The Gini coefficients of medical physicians in China are 0.003 and 0.88 by population and by service area, respectively. This shows that the distribution of medical physicians is fair basing on population, and there is little difference in the number of physicians per 1000 population in different regions. However, the physician distribution basing on service area is highly unfair and shows a large gap in the number of physicians per square kilometer between different regions. In general, Beijing, Zhejiang, Shanghai, Jiangsu, Shandong, and Tianjin are higher than the overall level of 31 provincial administrative regions. In addition, the number of medical physicians in Zhejiang, Shandong, Beijing and Jiangsu is over-provisioned., Conclusion: Bridging the number of medical physicians in different regions is a key step to improve the equity of physicians' resource allocation. Thus, findings from this study emphasize the need to take more measures to reduce physician quality differences between regions, balance and coordinate medical resources. This will increase the access of all citizens to quality medical services.

Background and Aims: Dyslipidemia and hypertension, key risk factors for cardiovascular disease, may share similar pathophysiological processes. A longitudinal association was reported between dyslipidemia and new-onset hypertension, but few data were published in Asian. We aimed to investigate the association of lipid profiles with new-onset hypertension in a Chinese community-based non-hypertensive cohort without lipid-lowering treatment (n = 1802)., Methods and Results: New-onset hypertension was defined as any self-reported history of hypertension, systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg, or receiving antihypertensive medications at follow-up. Logistic regression models were used to evaluate the associations. Participants were aged 53.97 ± 7.49 years, 31.19% were men, and 64.54% with dyslipidemia. During a median of 2.30 years follow-up, the incidence of new-onset hypertension was 12.99%. Multivariate adjusted risks of new-onset hypertension increased with triglyceride increases (odds ratio [OR] = 1.14, 95% confidence interval [CI]: 1.03-1.27) and high-density lipoprotein cholesterol (HDL-C) decreases (OR = 0.47, 95% CI: 0.29-0.76) for one unit. However, threshold effects were observed for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and non-HDL-C. Compared with subjects with hyperlipidemia, in those with normal concentrations of TC, LDL-C, and non-HDL-C increased risks of new-onset hypertension were observed with OR (95% CI) of 1.65 (1.10-2.46), 1.58 (1.07-2.33), and 1.57 (1.15-2.15) for one unit increasement, respectively, after adjusting for all covariates., Conclusion: Higher TG and lower HDL-C increased the risk of new-onset hypertension, but for TC, LDL-C and non-HDLC, the risk of new-onset hypertension was increased only at normal concentrations in a Chinese community-based cohort., (Copyright © 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Objective: Lumbar spondylolisthesis (LS) is a common lumbar disease, and the prevalence of LS in different countries or regions was not consistent in the past. This study intends to make statistics on the prevalence of lumbar spondylolisthesis in middle-aged people in Beijing community., Methods: This is an epidemiological study. 4548 people in Beijing community aged 50 to 64 years were recruited from the local communities by advertisements placed in housing estates and community centres for people to take part in a prospective cohort study from August from September 2013 to March 2014. There is no intervention on the subjects. RadiAnt DICOM Viewer is adopted to read the lateral CT positioning images of all the studied objects, adjust the image as bone window, observe and evaluate the slide of L1 to L5 vertebra in the lateral CT positioning image., Results: Among the 4,548 subjects included in the study, 2,490 (54.75%) were male and 2,058 (45.25%) were female. A total of 785 subjects had lumbar spondylolisthesis, with a total incidence of 17.26%. There was no significant difference between prevalence of males and females in the subgroup 50-54 years old (13.55% males / 12.53% females) and 55-59 years old (14.77% males / 14.93% females). But the prevalence of LS in 60-64 years old females (28.57%) increased significantly, compared with 55-59 years old females (14.93%) and 60-64 years old males (18.76%). There were 847 levels that had slipped, L5S1 > L4/5 > L3/4 > L2/3 > L1/2. The retrolisthesis was the most, accounting for 61.51% (521/847), and the anterolisthesis was 38.49% (326/847), including anterolisthesis gradeI for 95.71% (312/326), anterolisthesis gradeII for 4.29% (14/326). Neither of anterolisthesis and retrolisthesis presented more than grade III. Among all the subjects, 318 had anterolisthesis, with a total incidence of 6.99%, and 467 subjects only had retrolisthesis., Conclusion: The total prevalence of LS in the middle-aged people in Beijing community was 17.26%, 15.98% in males and 18.80% in females, and women are more likely to suffer from LS after 60 years old., (© 2021 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Measuring ammonia (NH 3 ) is important for understanding the role of NH 3 in secondary aerosol formation and the atmospheric deposition of reactive N. In this study, NH 3 was measured in an urban area, a background region, and a tunnel in Beijing. The average NH 3 concentrations between September 2017 and August 2018 were 24.8 ± 14.8 ppb and 11.6 ± 10.3 ppb in the urban area and background region, respectively. Higher NH 3 concentrations at both the urban and background sites, relative to some earlier measurements indicated a likely increase in the NH 3 concentrations in these regions. The urban NH 3 level in Beijing was much higher than that typically observed at urban and industrial sites in other domestic and foreign cities, suggesting that the Beijing urban area was affected by greater NH 3 emissions than other regions. Based on the relationship among NH 3 , wind direction, and wind speed, the urban area was affected by both local emissions and air transported from North China Plain (NCP). Potential source contribution function analyses suggested that regional transport from the NCP could greatly affect local concentrations of NH 3 in both urban and background areas in spring and autumn; however, in addition to the NCP, urban emissions could also affect NH 3 levels in the background region in summer and winter. The average NH 3 concentration at the Fenshuiling Tunnel was 8.5 ± 7.7 ppb from December 2017 to February 2018. The NH 3 :CO emission ratio measured in the tunnel test was 0.022 ± 0.038 ppb/ppb, which was lower than values in the USA and South Korea. The contribution of traffic to NH 3 in Beijing did not agree well with the available emission inventories, suggesting that vehicular emissions were underestimated and further evaluation is necessary., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Due to the accelerated process of urbanization in China, urban agglomerations have become the core areas for human settlement and economic development. High population and economic density has brought great pressure on water supply. Water scarcity is increasingly becoming one of the most important issues for the sustainable and healthy development of China's urban agglomerations. In this paper, a system dynamics model was constructed to simulate the current conditions and future scenarios of urbanization development and water scarcity in the Beijing-Tianjin-Hebei (BTH) urban agglomeration in 2000-2030, by examining the interaction and feedback between the six major subsystems: water supply, water demand, water pollution, population urbanization, economic urbanization, and land urbanization. It is found that the South-to-North Water Diversion Project and the improved Reclaimed Water Reuse System may greatly increase the water supply. However, the speed of population urbanization and economic growth, the spatial structure of urban agglomeration and the water consumption pattern may determine the water demand. Although all scenarios may risk water scarcity in the future at some point, we could detect a comprehensive and relatively rational scenario to balance water scarcity, regional equity, and efficiency. It might help to synthetically understand the coordinated development mode between urbanization and water resources in Beijing-Tianjin-Hebei (BTH) urban agglomeration, and provide a useful analytical and decision support tool for scientists and policy-makers to achieve the sustainable urbanization development and water resource management.