Evaluation of roadside air quality using deep learning models after the application of the diesel vehicle policy (Euro 6).

Euro 6 is the latest vehicle emission standards for pollutants such as CO, NO2 and PM, that all new vehicles must comply, and it was introduced in September 2015 in South Korea. This study examined the effect of Euro 6 by comparing the measured pollutant concentrations after 2016 (Euro 6-era) to the estimated concentrations without Euro 6. The concentration without Euro 6 was estimated by first modeling the air quality using various environmental factors related to diesel vehicles, meteorological conditions, temporal information such as date and precursors in 2002-2015 (pre-Euro 6-era), and then applying the model to predict the concentration after 2016. In this study, we used both recurrent neural network (RNN) and random forest (RF) algorithms to model the air quality and showed that RNN can achieve higher R2 (0.634 ~ 0.759 depending on pollutants) than RF, making it more suitable for air quality modeling. According to our results, the measured concentrations during 2016-2019 were lower than the concentrations predicted using RNN by - 1.2%, - 3.4%, and - 4.8% for CO, NO2 and PM10. Such reduction can be attributed to the result of Euro 6.

Wound healing efficacy of a chitosan-based film-forming gel containing tyrothricin in various rat wound models.

The objective of this study was to evaluate the healing effects of a chitosan-based, film-forming gel containing tyrothricin (TYR) in various rat wound models, including burn, abrasion, incision, and excision models. After solidification, the chitosan film layer successfully covered and protected a variety of wounds. Wound size was measured at predetermined timepoints after wound induction, and the effects of the film-forming gel were compared with negative (no treatment) and positive control groups (commercially available sodium fusidate ointment and TYR gel). In burn, abrasion and excision wound models, the film-forming gel enabled significantly better healing from 1 to 6 days after wound induction, compared with the negative control. Importantly, the film-forming gel also enabled significantly better healing compared with the positive control treatments. In the incision wound model, the breaking strength of wound strips from the group treated with the film-forming gel was significantly increased compared with both the negative and positive control groups. Histological studies revealed advanced granulation tissue formation and epithelialization in wounds treated with the film-forming gel. We hypothesize that the superior healing effects of the film-forming gel are due to wound occlusion, conferred by the chitosan film. Our data suggest that this film-forming gel may be useful in treating various wounds, including burn, abrasion, incision and excision wounds.