Field application of electrokinetic remediation for multi-metal contaminated paddy soil using two-dimensional electrode configuration.

In this study, we evaluated the feasibility of in situ electrokinetic remediation for arsenic (As)-, copper (Cu)-, and lead (Pb)-contaminated soil, in a pilot-scale field application with two-dimensional electrode configurations. Square and hexagonal configurations with different electrode spacing, 1 m and 2 m, were investigated under a constant 100 V. A square configuration with electrode spacing of 2 m removed 61.5 % of As, 11.4 % of Cu, and 0.9 % of Pb, respectively, and a hexagonal configuration with the same spacing showed a higher removal efficiency in top (59 % of As, 0-0.5 m) and middle (53 % of As, 0.5-1.0 m) layers, but much lower removal efficiency in the bottom layer (1-1.5 m), which was thought to be due to groundwater flow through periodic rise and fall of tides. Fractionation analysis showed that As bound to Fe-Mn oxyhydroxide was the main form of As removed by the electrokinetic process. The two-dimensional configuration wasted less electrical energy by Joule heating, and required fewer electrode installations, compared to the one-dimensional electrode configuration.

Electrokinetic remediation of Zn and Ni-contaminated soil.

The feasibility of catholyte conditioning with the acidic solution and pre-treatment of soil with acidic solution was investigated with the electrokinetic remediation of Zn and Ni contaminated field soil. The extraction of Zn and Ni from soil increased with the decrease in pH of the extracting solution and nitric acid was very effective to extract Zn and Ni from the soil. Conventional electrokinetic treatment and acetate buffer circulation method were not effective to remove Zn and Ni from the soil. Pre-treatment of the soil with acidic solution enhanced the desorption of Zn and Ni and catholyte conditioning with this solution was effective in maintaining the overall soil pH within the electrokinetic cell. The catholyte conditioning and pre-treatment method enhanced the removal of Zn and Ni up to 41% and 40% after operation for 4 weeks. More than 96% of Zn and Ni removed by electrokinetic remediation were due to the electromigration. Catholyte conditioning and the pre-treatment method is effective in enhancing metal removal in electrokinetic remediation.

Structural basis for the selective inhibition of JNK1 by the scaffolding protein JIP1 and SP600125.

The c-jun N-terminal kinase (JNK) signaling pathway is regulated by JNK-interacting protein-1 (JIP1), which is a scaffolding protein assembling the components of the JNK cascade. Overexpression of JIP1 deactivates the JNK pathway selectively by cytoplasmic retention of JNK and thereby inhibits gene expression mediated by JNK, which occurs in the nucleus. Here, we report the crystal structure of human JNK1 complexed with pepJIP1, the peptide fragment of JIP1, revealing its selectivity for JNK1 over other MAPKs and the allosteric inhibition mechanism. The van der Waals contacts by the three residues (Pro157, Leu160, and Leu162) of pepJIP1 and the hydrogen bonding between Glu329 of JNK1 and Arg156 of pepJIP1 are critical for the selective binding. Binding of the peptide also induces a hinge motion between the N- and C-terminal domains of JNK1 and distorts the ATP-binding cleft, reducing the affinity of the kinase for ATP. In addition, we also determined the ternary complex structure of pepJIP1-bound JNK1 complexed with SP600125, an ATP-competitive inhibitor of JNK, providing the basis for the JNK specificity of the compound.