Long-term exposure to air pollution and lung function among children in China: Association and effect modification

BackgroundChildren are vulnerable to the respiratory effects of air pollution, and their lung function has been associated with long-term exposure to low air pollution level in developed countries. However, the impact of contemporary air pollution level in developing countries as a result of recent efforts to improve air quality on children's lung function is less understood.MethodsWe obtained a cross-sectional sample of 617 schoolchildren living in three differently polluted areas in Anhui province, China. 2-year average concentrations of air pollutants at the year of spirometry and the previous year (2017–2018) obtained from district-level air monitoring stations were used to characterize long-term exposure. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory flow between 25 and 75% of FVC (FEF25−75) were determined under strict quality control. Multivariable regression was employed to evaluate the associations between air pollution level and lung function parameters, overall and by demographic characteristics, lifestyle, and vitamin D that was determined by liquid chromatography tandem mass spectrometry.ResultsMean concentration of fine particulate matter was 44.7 μg/m3, which is slightly above the interim target 1 standard of the World Health Organization. After adjusting for confounders, FVC, FEV1, and FEF25−75 showed inverse trends with increasing air pollution levels, with children in high exposure group exhibiting 87.9 [95% confidence interval (CI): 9.5, 166.4] mL decrement in FEV1 and 195.3 (95% CI: 30.5, 360.1) mL/s decrement in FEF25−75 compared with those in low exposure group. Additionally, the above negative associations were more pronounced among those who were younger, girls, not exposed to secondhand smoke, non-overweight, physically inactive, or vitamin D deficient.ConclusionsOur study suggests that long-term exposure to relatively high air pollution was associated with impaired lung function in children. More stringent pollution control measures and intervention strategies accounting for effect modification are needed for vulnerable populations in China and other developing countries

Remuneration Difference between Migrant Workers and Non-migrant Workers

Through the survey of direct economic remuneration, indirect economic remuneration and non-economic remuneration of employees in flat panel furniture enterprises in Chengdu City, we conduct a comparative analysis of the problems and causes of remuneration difference between migrant workers and non-migrant workers. The results show that the wage difference between migrant workers and non-migrant workers is the biggest, and there is little difference in terms of interests safeguarding and non-economic factors. The reason for the above results lies in the difference of education level; gender, region, household registration and other issues have little impact on the above results. The following recommendations are put forward to improve the remuneration of migrant workers: increasing government's policy advocacy efforts and eliminating subjective offense; establishing the administrative oversight bodies and effectively safeguarding the legitimate rights and interests of migrant workers; strengthening vocational training for migrant workers, so that workers have more choices on positions; improving the working environment and developing good working atmosphere

Effection of UV-LED Illuminant on the Curation of Photolatent-amidine Mixed with Bisphenol A Epoxy Acrylate under Printing Conditions

In order to make photocuring ink or coating cured by UV-LED illuminant, we synthesized (4-((hexahydropyrrolo[1,2-a]pyrimidin-1 (2H)-yl)methyl)phenyl)(phenyl)methanone(PL -DBN) and (4-((octahydropyrimido[1,2-a]azepin-1(2H)-yl)methyl)phenyl)(phenyl)met hanone(PL -DBU) as photoinitiators. Different mass fraction of the photoinitiators was mixed with bisphenol A epoxy acrylate, cured by different wavelengths and power of UV-LED illuminant,and investigated the curing effects of photoinitiators on bisphenol A epoxy acrylate. The results show that the conversion of C=C double bonds of bisphenol A epoxy acrylate will increase as the mass fraction of the photoinitiators or the power of UV-LED illuminant increase. In the same conditions, the curing effect of using 365nm UV-LED illuminant on bisphenol A epoxy acrylate is better than using 395nm UV-LED illuminant. PL-DBU has a better curing effect on the bisphenol A epoxy acrylate rather than PL-DBN. When using the 8W/cm2 of 365nm UV-LED illuminant to cure a mixture of 3% PL-DBU and 97% bisphenol A epoxy acrylate, it will be dry completely in 2 seconds, moreover, the conversion reach 79%

Effection of UV-LED Illuminant on the Curation of Photolatent-amidine Mixed with Bisphenol A Epoxy Acrylate under Printing Conditions

In order to make photocuring ink or coating cured by UV-LED illuminant, we synthesized (4-((hexahydropyrrolo[1,2-a]pyrimidin-1 (2H)-yl)methyl)phenyl)(phenyl)methanone(PL -DBN) and (4-((octahydropyrimido[1,2-a]azepin-1(2H)-yl)methyl)phenyl)(phenyl)met hanone(PL -DBU) as photoinitiators. Different mass fraction of the photoinitiators was mixed with bisphenol A epoxy acrylate, cured by different wavelengths and power of UV-LED illuminant,and investigated the curing effects of photoinitiators on bisphenol A epoxy acrylate. The results show that the conversion of C=C double bonds of bisphenol A epoxy acrylate will increase as the mass fraction of the photoinitiators or the power of UV-LED illuminant increase. In the same conditions, the curing effect of using 365nm UV-LED illuminant on bisphenol A epoxy acrylate is better than using 395nm UV-LED illuminant. PL-DBU has a better curing effect on the bisphenol A epoxy acrylate rather than PL-DBN. When using the 8W/cm2 of 365nm UV-LED illuminant to cure a mixture of 3% PL-DBU and 97% bisphenol A epoxy acrylate, it will be dry completely in 2 seconds, moreover, the conversion reach 79%

Simulation and Optimization of Strengthening the Gas-Liquid Mass Transfer Structure in Tray Column

This paper presented the analysis of the effect of the mesh layers, installation height and opening rate on gas-liquid two-phase flow field by numerical simulation, which based on Euler-Euler model and identified the best liquid-gas ratio. The simulation results showed that: when the installation height of the square mesh was 25 mm and opening rate was 55.7%, the gas holdup distribution in the upper part of the mesh became higher and improved the liquid velocity distribution. Meanwhile, the gas-liquid distribution on trays was more uniform

Hierarchical constraint geological modelling method for carbonate paleokarst caves: A case study of Ordovician fracture-cavern unit in Tahe Oilfield

The characteristics of carbonate paleokarst cave and filling have always been the difficulty of characterization and modelling. Based on the seismic, geological and logging data, this paper puts forward the idea of three-level progressive modelling of karst cave complex, single karst cave and karst cave internal filling. The karst cave complex is a large-scale geological body, which can be identified by seismic in most cases. The truncated Gaussian simulation method is used to establish the karst cave complex model; the single karst cave belongs to the medium-scale geological body, and which is difficult to beidentified by seismic. Based on a large number of outcrops measured data, the single karst cave distribution model is established by using the target based indicative point process simulation method; the internal filling of karst cave is small.It is barely recognizable by seismic waves at current resolutions. The multi-point geostatistics method is applied to establish a single karst cave internal filling structure model. The "three-step" modeling idea of hierarchical constraint can gradually reduce the uncertainty of geological model, improve the accuracy of geological modelling.The new idea was tested by a case study in a fracture-cavity unit in Tahe Oilfield, and the related issues and study directions of the new idea were discussed. The test results indicate that the "three-step" modeling idea karst cave reservoir, and the implementation effect is remarkable