Ammonia (NH 3 ) emissions from intensive anthropogenic activities is an important component in the global nitrogen cycle that has triggered large negative impacts on air quality and ecosystems worldwide. An accurate spatially explicit high resolution NH 3 emission inventory is essential for modeling atmospheric aerosol pollution and nitrogen deposition. However, existing NH 3 emission inventories in China are still subject to several uncertainties. In this review we firstly summarize the widely used methods for the estimate of NH 3 emissions and discuss their advantages and major limitations. Secondly, we present aggregated data from ten NH 3 emission inventories to assess the trends in total anthropogenic NH 3 emissions in China over the period 1980–2019. Almost emission estimates reported that NH 3 emissions in China have doubled in the last four decades. We find a substantial differences in annual total NH3 emissions, spatial distributions and seasonal variations among selected datasets. In 2012, the median emission (Tg yr −1 ) and associated minimum-maximum ranges are 12.4 (8.5 _ 17.2) for total emission, 9.9 (8.1 _ 13.8) for agriculture, 0.3 (0.2 _ 1.0) for industry, 0.4 (0.2 _ 1.1) for residential and 0.1 (0.1 _ 0.3) for transport and other emission of 1.5 (0.3 _ 2.6). In general, peak emissions occur in summer but in different months, the higher NH 3 emission intensities are concentrated in the NCP area, and in eastern and south-central China but distinct regional discrepancy among selected datasets. Finally, we made an analysis of the reasons and levels of difference in NH 3 emission estimates with recommendations for improvement of China’s NH 3 emission inventory.
Plastic debris (including macro-plastics, microplastics (MPs), and nanoplastics), defined as an emerging contaminant, has been proven to significantly affect soil ecosystem functioning. Accordingly, there is an urgent need to robustly quantify the pollution situation and potential sources of plastics in soils. China as the leading producer and user of agricultural plastics is analyzed as a typical case study to highlight the current situation of farmland macro-plastics and MPs. Our study summarized information on the occurrence and abundance of macro-plastics and MPs in Chinese farmland soils for the first time based on 163 publications with 728 sample sites. The results showed that the average concentration of macro-plastics, and the abundance of MPs in Chinese farmlands were 103 kg ha−1 and 4537 items kg−1 (dry soil), respectively. In addition, this study synthesized the latest scientific evidence on sources of macro-plastics and MPs in farmland soils. Agricultural plastic films and organic wastes are the most reported sources, indicating that they contribute significantly to plastic debris in agricultural soils. Furthermore, the modeling methods for quantifying macro-plastics and MPs in soils and estimating the stock and flow of plastic materials within agricultural systems were also summarized.
Abstract. The Chinese government recently proposed ammonia (NH3) emission reductions (but without a specific national target) as a strategic option to mitigate fine particulate matter (PM2.5) pollution. We combined a meta-analysis of nationwide measurements and air quality modeling to identify efficiency gains by striking a balance between controlling NH3 and acid gas (SO2 and NOx) emissions. We found that PM2.5 concentrations decreased from 2000 to 2019, but annual mean PM2.5 concentrations still exceeded 35 µg m−3 at 74 % of 1498 monitoring sites during 2015–2019. The concentration of PM2.5 and its components were significantly higher (16 %–195 %) on hazy days than on non-hazy days. Compared with mean values of other components, this difference was more significant for the secondary inorganic ions SO, NO, and NH (average increase 98 %). While sulfate concentrations significantly decreased over this period, no significant change was observed for nitrate and ammonium concentrations. Model simulations indicate that the effectiveness of a 50 % NH3 emission reduction for controlling secondary inorganic aerosol (SIA) concentrations decreased from 2010 to 2017 in four megacity clusters of eastern China, simulated for the month of January under fixed meteorological conditions (2010). Although the effectiveness further declined in 2020 for simulations including the natural experiment of substantial reductions in acid gas emissions during the COVID-19 pandemic, the resulting reductions in SIA concentrations were on average 20.8 % lower than those in 2017. In addition, the reduction in SIA concentrations in 2017 was greater for 50 % acid gas reductions than for the 50 % NH3 emission reductions. Our findings indicate that persistent secondary inorganic aerosol pollution in China is limited by emissions of acid gases, while an additional control of NH3 emissions would become more important as reductions of SO2 and NOx emissions progress.
Nickel (ii) (Ni2+) is considered as one of the necessary trace elements in the process of Anammox culture, but it may have toxic effects at high concentration. This study explored the long-term influence of Ni2+ on the denitrification efficiency of Anammox bioreactors. The results showed that when the concentration of Ni2+ was 0.5 mg/L, the bioreactor had the highest denitrification efficiency, while the removal efficiency of ammonia nitrogen and nitrite nitrogen gradually decreased at concentrations higher than 2 mg/L, and the removal rates of ammonia nitrogen and nitrite nitrogen were 26% and 39.81% at the end of the experiment, respectively. The NRR was decreased from 7.47 kg N/m3 d to 3.28 kg N/m3 d during the whole process. The highest concentration of microbial dehydrogenase was attained in about 40 days; in the meantime, its ability to consume organic matter was also maximized. The sludge morphology was changed from granular cluster to loose flocculant with a small number of spherical and filamentous bacteria and bacilli distributed on the surface. At the end of the experiment, both species richness and community diversity were reduced, and the proportion of the dominant bacteria Candidatus Kuenenia was also decreased from 59.89% to 36.72%.
Purpose: Vitiligo is a T cell-mediated skin depigmentation disease. Though treatments arresting disease progression and inducing repigmentation are available, the efficacy of these options is often limited and poorly sustained. How stromal signals contribute to the interferon-γ-dominant skin niches is unclear. This study aims to determine how fibroblasts participate in the IFN-γ-dominant vitiligo niche. Patients and methods: Mouse vitiligo models were established. Fibroblasts from control and vitiligo mice were extracted for RNA sequencing. In vitro IFN-γ stimulation was performed to verify the JAK-STAT pathway by qPCR and Western blot. T cell polarization with chemokines was measured by flow cytometry. Protein levels in tissues were also examined by IHC. Results: The vitiligo mouse model recapitulates the human CD8-IFN-γ pathway. RNA sequencing revealed elevated chemokine CCL2 and CCL8 in vitiligo fibroblast, which may be regulated by the JAK-STAT signaling. Such phenomenon is verified by JAK inhibitor peficitinib in vitro. Moreover, CCL2 addition into the naïve T polarization system promoted type 2 cytokines secretion, which represents a hallmark of vitiligo lesions. Conclusion: Dermal fibroblasts, a principal constituent of skin structure, respond to IFN-γ by skewing T cells towards a type 2 cytokine profile via CCL2 and CCL8, which can be abrogated by JAK inhibitor peficitinib.
Abstract Terrestrial ecosystems in China receive the world’s largest amount of reactive nitrogen (N) deposition. Recent controls on nitrogen oxides (NO x = NO + NO 2 ) emissions in China to tackle air pollution are expected to decrease N deposition, yet the observed N deposition fluxes remain almost stagnant. Here we show that the effectiveness of NO x emission controls for reducing oxidized N (NO y = NO x + its oxidation products) deposition is unforeseen in Eastern China, with one-unit reduction in NO x emission leading to only 55‒76% reductions in NO y -N deposition, as opposed to the high effectiveness (around 100%) in both Southern China and the United States. Using an atmospheric chemical transport model, we demonstrate that this unexpected weakened response of N deposition is attributable to the enhanced atmospheric oxidizing capacity by NO x emissions reductions. The decline in N deposition could bear a penalty on terrestrial carbon sinks and should be taken into account when developing pathways for China’s carbon neutrality.
The Chinese economic reform has recently become a major focus of attention around the world. The underlying rationale for the Chinese government's privatisation and public sector reforms is the view that reformed state enterprises and privately managed firms will demonstrate superior management control and better performance, and hence encourage economic growth and employment. There are very few intensive case studies published in English journals studying whether firms privatised in China have reversed previous losses and introduced better management controls, leading to increased investment, productivity, and overall organizational effectiveness and efficiency. The researchers do not seek to deny the control problems of Chinese SOEs, but question the consequences of the new controls installed during the post-privatisation period. The paper also reveals a declining tendency in employment; altered distributions of wealth – especially to the state – and labour, and a lack of improvements in the accountability of privatised companies. Overall, the paper argues, the aims of reform policies in China, including better control, increased profitability and an improved working life for Chinese people, have not materialized. The paper calls for more research on the above issues in the Chinese context.
This paper studies the single-sideband RF signals in the optical carrier side than the problem. RF signals modulated optical carrier OSSB + C modulation index is usually small, leading edge modulated carrier radio frequency signal generated by the optical carrier ratio is not ideal. A design scheme based on three-arm and four-arm MZM MZM optimized optical carrier single sideband radio frequency signal containing the edge ratio. By adjusting the DC bias voltage of the modulator can control the carrier side than the light signal. For any modulation index, are able to make the optical carrier single sideband radio frequency signal containing edges than the optimal value of 0 dB, improving the performance of the system. The simulation also verify their feasibility.
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