Dynamic emission characteristics and control strategies of air pollutants from motor vehicles in downtown Beijing,China

This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing.A dynamic emission inventory of motor vehicle air pollutants in downtown Beijing in 2021 was established,and the impact of these emissions on air quality was simulated and quantified,and different emission reduction control scenarios were proposed to evaluate their environmental improvement effects and explore measures to mitigate the impact of pollution emissions.The results show that the high traffic flow and the structure of the motor vehicle emissions in downtown Beijing are the main causes of severe motor vehicle pollution.Monitoring data shows that traffic flow in central Beijing is dominated by small passenger vehicles,while the vehicle mix is better than in other regions,with 72.0%of vehicles meeting"National V"or higher emission standards.However,to achieve higher air quality goals,further reducing vehicle emissions is necessary.Based on dynamic traffic flow,the average daily emissions of nitrogen oxides(NOX),particulate matters(PM_(2.5))and volatile organic compounds(VOC)from motor vehicles in central Beijing are 17.7 tons,0.6 tons and 14.0 tons,respectively,accounting for 23.0%of the city’s average daily motor vehicle emissions.If a zero-emission zone for motor vehicles were implemented in central Beijing,the annual average emission level of pollutants will be reduced by 10.4%to 21.0%.The designation of ultra-low emission zones for motor vehicles could be effective in improving the air quality in the center of Beijing.

Vehicle emissions of primary air pollutants from 2009 to 2019 and projection for the 14th Five-Year Plan period in Beijing, China

Over the past decade,the emission standards and fuel standards in Beijing have been upgraded twice,and the vehicle structure has been improved by accelerating the elimination of 2.95 million old vehicles.Through the formulation and implementation of these policies,the emissions of carbon monoxide(CO),volatile organic compounds(VOCs),nitrogen oxides(NO_(x)),and fine particulate matter(PM_(2.5))in 2019 were 147.9,25.3,43.4,and 0.91 kton in Beijing,respectively.The emission factor method was adopted to better understand the emissions characteristics of primary air pollutants from combustion engine vehicles and to improve pollution control.In combination with the air quality improvement goals and the status of social and economic development during the 14th Five-Year Plan period in Beijing,different vehicle pollution control scenarios were established,and emissions reductions were projected.The results show that the emissions of four air pollutants(CO,VOCs,NO_(x),and PM_(2.5))fromvehicles in Beijing decreased by an average of 68% in 2019,compared to their levels in 2009.The contribution of NOx emissions from diesel vehicles increased from 35% in 2009 to 56% in 2019,which indicated that clean and energy-saving diesel vehicle fleets should be further improved.Electric vehicle adoption could be an important measure to reduce pollutant emissions.With the further upgrading of vehicle structure and the adoption of electric vehicles,it is expected that the total emissions of the four vehicle pollutants can be reduced by 20%-41% by the end of the 14th Five-Year Plan period.

Liver cell therapies:cellular sources and grafting strategies

The liver has a complex cellular composition and a remarkable regenerative capacity.The primary cell types in the liver are two parenchymal cell populations,hepatocytes and cholangiocytes,that perform most of the functions of the liver and that are helped through interactions with non-parenchymal cell types comprising stellate cells,endothelia and various hemopoietic cell populations.The regulation of the cells in the liver is mediated by an insoluble complex of proteins and carbohydrates,the extracellular matrix,working synergistically with soluble paracrine and systemic signals.In recent years,with the rapid development of genetic sequencing technologies,research on the liver’s cellular composition and its regulatory mechanisms during various conditions has been extensively explored.Meanwhile breakthroughs in strategies for cell transplantation are enabling a future in which there can be a rescue of patients with end-stage liver diseases,offering potential solutions to the chronic shortage of livers and alternatives to liver transplantation.This review will focus on the cellular mechanisms of liver homeostasis and how to select ideal sources of cells to be transplanted to achieve liver regeneration and repair.Recent advances are summarized for promoting the treatment of end-stage liver diseases by forms of cell transplantation that now include grafting strategies.

Quantitative Characterization of the Elasticity,Net Creep,and Swelling of the Intervertebral Disc:An In Vitro Experiment

During the in vitro creep of intervertebral discs,both applied loads and osmosis of solution influence their biomechanical behaviors.More specifically,the total displacement can be attributed to three parts:the elastic response during the loading period that results from instant tissue deformation;the nonlinear displacement during the creep period that is due to the poro-elastic fluid flow and visco-elastic deformation;and the swelling of discs that are affected by the osmolality.However,their respective contributions to the total displacement are unknown.To this end,this study aims to discern contributions of the above three parts in ex vivo experiments quantitively.Specimens were compressed for 4 h after 0.5 h preload.Displacement and strain were recorded and curve-fitted.The instant elastic displacement was positively related to the applied load,and its proportion rose from 18.09 to 21.46% as the load elevated.While the contribution of the net creep was inversely related to the applied load,dropping from 74.49 to 60.16%.An increase of 0.74 MPa of the osmolality induced a rise in displacement by 7.42-18.38%.Moreover,with the help of the non-contact measurement,researchers are able to know the contribution of each part quantitatively,which is of importance in understanding the creep mechanisms and developing biomaterials with mechanical mimicry of natural discs.

Ten-year emission characteristics of atmospheric pollutants from incineration of sacrificial offerings in China

The incineration of sacrificial offerings is a significant widely practiced custom that is also a kind of neglected air pollution source in China.Our results showed that the emission factors of particulate matter,SO_(2),CO,NO_(x),and VOCs emitted from the incineration of sacrificial offerings with purification systems were reduced by 95%,19%,9%,82%,and 42%,respectively,compared with those without a purification system,revealing a significant effect of the flue gas purification system on reducing particulate matter and gaseous pollutants.The emission level of air pollutants from the incineration of sacrificial offerings remained stable before 2013 and then showed a remarkable decrease after the implementation of China′s Air Pollution Prevention Action Plan in 2013.The emissions of TSP(total suspended particulate),PM_(10),PM_(2.5),and NO_(x)in 2009 were 8222,6106,5656 and 15,878 ton,respectively,obviously higher than 3434,2551,2305 and 8579 ton in 2019.Such trend was affected by both the quantity of incineration and the installation rate of purification systems after the Emission Standard of Air Pollutants for Crematory(GB 13801-2015)issued in China.Distinct spatial distribution of atmospheric pollutants from incineration of sacrificial offerings was found with higher in the east and south of China than the west and north of China,which is proportional to the regional economy and population.The maximum ground-level concentration typically occurred at 0.12-0.2 km from the pollution source,posing potential health risks to people entering and exiting funeral and burial sites and nearby residents.

Developments in diagnostic applications of saliva in human organ diseases

Saliva is one of the important body fluids that reflects normal internal characteristics and disease state of an individual.As a multi-composition oral fluid,has high potential for the surveillance of general health and disease,which contains various disease signal biomarkers and is non-invasive,convenient,fast and easy to be accepted by patients.At present,saliva is increasingly used as a biological fluid for diagnosis,monitoring systemic disease states and predicting disease progression,which has been verified.In this review,the molecular compositions and effectiveness of saliva as reliable biological fluid were discussed.Besides the latest research progress in the diagnosis of saliva related to 14 organs were reviewed.The factors affecting saliva diagnosis were discussed.The method to improve the accuracy of prediction through artificial intelligence combined with microfluidic chip was proposed,which laid the foundation for dealing with the prevention,diagnosis,and treatment of related diseases through saliva with great and long-term significance.