Search Results (2)

Soil acidification activates most of the cationic heavy metals in soil and thus enhances their accumulation in crops, posing an accentuated threat to human health, while there is limited knowledge regarding the accumulation of metalloid arsenic (As) in crops, which is influenced by acidification due to its opposite behavior in soil. In this study, the acidification processes of neutral purple soil together with the accompanied changes in soil properties and As fractionation were examined through a column-leaching experiment. Subsequently, growth and As accumulation in pakchoi (Brassica campestris L.) were investigated under various combinations of soil pH and As pollution levels in a pot experiment. This allowed us to elucidate the mechanisms of As accumulation in pakchoi under the co-stresses of soil acidification and As pollution. The results indicated that soil acidification followed a two-phase process, initially rapid and later slow, with a turning point at a pH of 4.7–4.8. Below this critical pH, the leaching rates of base ions and As accelerated significantly and the decomposition of primary minerals began, primarily from chlorite to green/mesospheric minerals, resulting in a substantial increase in the content of amorphous iron oxide. Meantime, soil As was transformed from highly labile forms, such as non-specifically and specifically adsorbed forms, to less active ones like amorphous hydrous oxide-bound and residual forms, resulting in decreased As availability. In this context, As pollution remarkably delayed the growth of pakchoi, while the influence of acidification on growth only occurred when the soil was acidified to a pH lower than 6, as demonstrated by a substantial biomass reduction at higher As levels and a 41.8% biomass decrease at pH 4.6. Moreover, soil acidification exacerbated the inhibitory effect of As on pakchoi growth. The As contents in the edible parts of pakchoi dramatically increased with the increase in the soil As level, and soil acidification did not mitigate As accumulation in plants via the suppression of soil As availability but rather greatly increased it due to the bioconcentration effect caused by As toxicity. In conclusion, significant interactions existed between soil acidification and As pollution in terms of soil properties and As transformation, leading to comprehensive effects on growth and As accumulation in crops. Full article

As per sequential studies on new types of soft rubber for the artificial skin of robots, smart sensors, etc., we have proposed and investigated hybrid skin (H-Skin) and haptic sensors by using magnetic compound fluid (MCF), compounding natural rubber latex (NR-latex), and applying electric and magnetic fields. Through electrolytic polymerization, the MCF rubber is solidified. The MCF rubber has hybrid sensing functions and photovoltaic effects, and electric charge as battery. In case of the production of soft rubber sensors, however, the problem of adhesion between metal electrodes and rubber is very important. In the present study, we propose a novel adhesive technique for bonding the metal electrodes and MCF rubber by using metallic or non-metallic hydrous oxide, which is a metal complex, via electrolytic polymerization. The anionic radical hydrate reacts with the isoprene molecules of NR-latex or chloroprene rubber latex (CR-latex) such that they are cross-linked and the MCF rubber with the hydrate is solidified, which can be represented via a chemical reaction equation. By means of this adhesive technique, we presented five cases of sensors fabricated using metal electrodes and rubbers. This technique is applicable for novel cohesion between rubber and metal. Full article