Investigation of simultaneous effects of noise barriers on near-road noise and air pollutants.

Noise barriers are one of the common solutions to control road traffic noise. Many studies have also shown that noise barriers cause reductions in near-road air pollutant concentrations. In this study, the simultaneous effects of a specific noise barrier application on near-road noise and air pollution at a specific location were investigated. In this context, air pollution, noise, and meteorological parameters were measured simultaneously at two points, road and receptor sides of a 50 m long, 4 m high glass fiber reinforced concrete noise barrier on a highway section. Results indicated that the noise barrier has an average 23 % reduction effect on the NOx concentration in addition to the noise level reduction at the receptor side. Besides, bi-weekly average passive sampler measurement results for BTEX pollutants indicate lower values at the receptor side of the barrier compared to the free field measurement results. In addition to real-time and passive sampler measurements, NOx and noise dispersions were modeled using RLINE and SoundPLAN 8.2 software, respectively. Comparisons of the measurement results with the model results indicated strong correlations. Model-calculated NOx and noise values under the free field conditions are highly compatible with a correlation coefficient (r) of 0.78. Although the noise barrier has a reduction effect on both parameters, it has been observed that their dispersion mechanisms are different. This study showed that noise barriers considerably affect the dispersion of road-sourced air pollutants at the receptor side. Further studies are needed to optimize noise barrier designs with different physical and material properties and application scenarios considering noise and air pollutants together.

Aluminum doped carbon nanodots as potent adjuvants on the mammalian macrophages.

In this manuscript, we aimed to report the synthesis of aluminum (Al) incorporated carbon nanodots (CD) and their activities on the immune cells. A green synthesis method involving the in situ doping of the nanodot was conducted. Synthesized nanodots immunomodulatory and immunostimulatory activities were tested in vitro on the macrophages. The produced carbon dots were water-soluble, fluorescent and monodispersed, with an average diameter of around 10-20 nm. After Al-doping, their surface properties, stability, crystallinity, as well as their fluorescent and optical properties were evaluated. These Al-CDs displayed no cytotoxicity and enhanced the pro-inflammatory activities of the mammalian macrophages with much lower aluminum concentrations (‰ 20) compared to that of conventional aluminum salt, by virtue of which they have the potential to serve as safe and effective adjuvant carrier. The stability of the nanocarriers was found to be persistent for over 3 months at room temperature with no significant formation of the aggregates. These results support the promise of such nanodots as the new generation non-toxic adjuvant candidates. Al incorporation changed the activity of carbon nanodot (CD). Plain CD did not have major affect on the inflammatory function of macrophages. Al incorporated CD was able to stimulate the macrophages in the absence of danger stimulus which supports its adjuvant potential. Compared to the Al salt as a control Al-CD was more potent even with ‰ 20 Al concentration on the inflammatory activity of the macropahges in vitro.