Meteorological Change and Impacts on Air Pollution: Results From North China

There have been speculations that the severe air pollution experienced in North China was the act of meteorological change in general and a decreasing northerly wind in particular. We conduct a retrospective analysis on 1979–2016 reanalysis data from ERA‐Interim of European Centre for Medium‐Range Weather Forecasts over a region in North China to detect meteorological changes over the 38 years. No significant reduction in the northerly wind within the mixing layer is detected. Statistically significant increases are detected in the surface temperature, boundary layer height and dissipation, and significant decreases in relative humidity in the region between the first and second 19‐year periods from 1979 to 2016. We build regression models of PM2.5 on the meteorological variables using data in 2014, 2015, and 2016 to quantify effects of the meteorological changes between the two 19‐year periods on PM2.5 under the emission scenarios of 2014–2016. It is found that despite the warming, dew point temperature had been largely kept under control as the region had gotten dryer. This made the effects of temperature warming largely favorable to PM2.5 reduction as it enhances boundary layer height and dissipation. It is found that the meteorological changes would lead to 1.29% to 2.76% reduction in annual PM2.5 averages with January, March, and December having more than 4% reduction in the 3 years. Thus, the meteorological change in North China had helped alleviate PM2.5 to certain extent and should not be held responsible for the regional air pollution problem.Key PointsMeteorological changes led to 1.9% to 2.7 percent% reduction in annual PM2.5 averages over North China 2014 to 2016 driven by temperature warmingSignificant increases are detected in the surface temperature, boundary layer height, and dissipation and decreases in relative humidityThe meteorological change should not be held responsible for the regional air pollution problem in North ChinaPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/3/jgrd56226_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/2/jgrd56226.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/1/jgrd56226-sup-0001-Figure_SI-S01.pd

The pre-stack migration imaging technique for damages identification in concrete structures

AbstractPre-stack migration imaging (PMI) method, which is used in geophysical exploration by the performance of single side detection and visually display, can be used to identify the location, orientation, and severity of damages in concrete structure. In particular, this letter focuses on the experimental study by using a finite number of sensors for further practical applications. A concrete structure with a surface-mounted linear PZT transducers array is illustrated. Three types of damages, horizontal, dipping and V-shaped crack damage, have been studied. A pre-stack reverse time migration technique is used to back-propagate the scattering waves and to image damages in concrete structure. The migration results from the scattering waves of an artificial damage are presented. It is shown that the existence of the damage in concrete structure is correctly revealed through migration process

Effect of aging on acute pancreatitis through gut microbiota

BackgroundCompared to younger people, older people have a higher risk and poorer prognosis of acute pancreatitis, but the effect of gut microbiota on acute pancreatitis is still unknown. We aim to investigate the effect of aging gut microbiota on acute pancreatitis and explore the potential mechanism of this phenomenon.MethodsEighteen fecal samples from healthy adult participants, including nine older and nine younger adults were collected. C57BL/6 mice were treated with antibiotics for fecal microbiota transplantation from older and younger participants. Acute pancreatitis was induced by cerulein and lipopolysaccharide in these mice. The effect of the aged gut microbiota was further tested via antibiotic treatment before or after acute pancreatitis induction.ResultsThe gut microbiota of older and younger adults differed greatly. Aged gut microbiota exacerbated acute pancreatitis during both the early and recovery stages. At the same time, the mRNA expression of multiple antimicrobial peptides in the pancreas and ileum declined in the older group. Antibiotic treatment before acute pancreatitis could remove the effect of aging gut microbiota, but antibiotic treatment after acute pancreatitis could not.ConclusionAging can affect acute pancreatitis through gut microbiota which characterizes the deletion of multiple types of non-dominant species. This change in gut microbiota may potentially regulate antimicrobial peptides in the early and recovery stages. The level of antimicrobial peptides has negative correlations with a more severe phenotype