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Recently, materials with controllable superwettability have attracted much attention. However, almost all studies focused on controlling wetting of water and oil; research on underwater gas bubble wetting control is still rare. Herein, we report a mesh film prepared by coating polypyrrole (PPy) film on Ti mesh. Briefly, the film mesh is underwater superaerophilic when PPy is doped with perfluorooctanesulfonate ions (PFOS - ), and becomes underwater superaerophobic as the PFOS - are removed. The transition of the wettability can be triggered by electrical stimuli, which is attributed to the cooperative effect between the rough structure and chemical components variation. The controllable wettability allows adjustable bubble permeation. It can be envisioned that the film will provide potential applications in the future, such as underwater bubble capture/release and microfluidic devices., (© 2022 Wiley-VCH GmbH.)

The effects of a 50% forest thinning intensity on Fukushima-derived 137 Cs deposition by litterfall and its discharge by runoff in hillslope coniferous forest were monitored using four litterfall traps and a hillslope erosion plot. The observation was underway during the pre-and post-thinning periods. Results demonstrated that during the pre-thinning period a total 150 ± 13 g m -2 of litterfall deposited about 924 ± 69 Bq m -2 of 137 Cs. This accounts for 11% of the local 137 Cs fallout recorded for the study site in the aftermath of the accident. After thinning, both litterfall and 137 Cs increased by more than six- and two-fold, respectively. This is possibly owing to the slow individual tree recovery rate assisted by the change on the running space provided by canopy openings, which can accelerate even the normal gust wind to gain damaging power on the unshielded mechanically injured parts of the contaminated residual trees. In both cases, litterfall generally transferred about 37% (3 ± 0.2 kBq m -2 ) of the local 137 Cs fallout onto the forest floor over the observation period. The eroded litter-associated 137 Cs increased by about a factor of two after thinning, which only accounted for less than 1% of 137 Cs deposited by litterfall. This implies that the forest floor retains 137 Cs and remains contaminated regardless of the size of the eroded litter material. But this could become a potential secondary contamination source for the downstream resources such as water bodies and villages, especially at the time of flooding, which in turn calls a serious attention in designing decontamination schemes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Knowledge of the characteristics of chemical components transported in the xylem sap of trunks remains deficient and limited because no appropriate method exists to extract the xylem sap from this part of the tree. We thus explored the differences in xylem sap components extracted by means of centrifugation and water displacement methods and depicted the level and behavior of chemical components in the xylem sap of trunks and branches of different aged trees from a pine forest in northern China. There were no significant differences between the two methods with respect to nitrogen (N) compounds and inorganic ions in the xylem sap. Potassium concentrations obtained by the methods were similar and consistent with the values obtained from earlier publications on woody species. This suggests that contamination of the xylem sap by the centrifugation method is negligible, and this method would be a reliable and robust tool for collection of the trunk xylem sap. Dissolved organic N was the dominant component of total N followed by nitrate (NO 3 - ) and ammonium (NH 4 + ). Potassium and chloride were the predominant cation and anion, respectively, of the xylem sap. The NO 3 - concentration basically did not change, whereas the NH 4 + concentration was larger transported from the trunk to branches for the large tree class during foliage senescence. More inorganic N components (mainly NO 3 - ) were found in young trees than in old trees. Our study contributes to improve the diagnostic assessments of tree physiological processes and growth in mature forest trees under environmental changes., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

A wide area of paddy fields was contaminated by radiocesium derived from the Fukushima nuclear accident. Implement of agricultural countermeasures is one of the principle methods to reduce the contamination of rice plants. In this study, the effect of topsoil removal measure and fertilizer application on radiocesium uptake by rice plants was investigated over a four-year period. Some other available countermeasures carried out after the Fukushima nuclear accident were also summarized. The results indicate that the effect of topsoil removal measure on the accumulation of radiocesium in rice plants was effective, but the concentration ratio of radiocesium activity concentration between rice plant and soil increased. This may be correlated with the radiocesium imported from irrigation water and relatively high exchangeable radiocesium proportion of plowing soil in the topsoil removal paddy. We summarized four year's data to further confirm that potassium and nitrogen fertilizers had an opposite effect on the accumulation of radiocesium in rice plants. Increasing potassium and reducing nitrogen fertilizer conditions tended to inhibit the radiocesium uptake by rice plants. Moreover, of all the available countermeasures applied in the paddy fields, the most effective countermeasure was the application of phlogopite. However, further analyses are required to confirm the effectiveness of application of phlogopite considering the limited available information., (Copyright © 2017 Elsevier B.V. All rights reserved.)