Characterization and thermodynamic study of humic acid in deep groundwater at Horonobe,Hokkaido, Japan

In this study, humic substances (humic acid and fulvic acid) were isolated from deep groundwater at ?350 m depth of Horonobe, Hokkaido, Japan to compare the characteristic property and reaction mechanism with generic humic acid isolated from surface soils. The size distributions of Horonobe humic substances were analyzed by size exclusion chromatography, flow-field flow fractionation, and total organic carbon measurement with ultrafiltration. All of them indicated small molecular weight and particle size of Horonobe humic acid in comparison with generic humic acids. Additionally, the simple protonation behavior of Horonobe humic substances similar to benzoic acid and/or phenol was revealed by thermodynamic quantities obtained by potentiometry and calorimetry. Consequently, molecular size and the reaction mechanism of Horonobe humic substances are different from generic humic acids, due to the characteristic origin.     

[{W(O)(O2)2(H2O)}2(μ‐O)]2–‐Catalyzed Epoxidation of Allylic Alcohols in Water with High Selectivity and Utilization of Hydrogen Peroxide

A dinuclear peroxotungstate, K₂[{W(O)(O₂)₂(H₂O)}₂(μ‐O)]⋅2 H₂O, exhibits high catalytic performance for the epoxidation of various allylic alcohols with only one equivalent of hydrogen peroxide at 305 K in water solvent. The effectiveness of this system is evidenced by high chemo‐, regio‐, and diastereoselectivity, and stereospecificity for the epoxidation of allylic alcohols. Furthermore, products/catalyst separation can be easily carried out by simple extraction and the catalyst recovered can be reused with the maintenance of the catalytic performance.     

Detection of abnormal fish by image recognition using fine-tuning

Artificial Life and Robotics - Fishermen need to remove abnormal or dead fish for the prevention of viral infection. However, the identification of diseased fish is more ambiguous that the...     

Adaptive optimal stimulus selection in cognitive models using a model averaging approach

Behaviormetrika - Stimulus selection based on the maximum Fisher information (MFI) principle enables the efficient estimation of participant parameters of cognitive models with elaborated...