Pesticide adsorption by granular activated carbon adsorbers. 2. Effects of pesticide and natural organic matter characteristics on pesticide breakthrough curves

The principal objective of this study was to elucidate mechanisms by which NOM affects the adsorption of a nonpolar (simazine) and a polar (asulam) herbicide on activated carbon. Experiments were carried out in microcolumns that were continuously fed solutions containing NOM with different molecular weight (MW) distributions and intermittently solutions containing the same NOM plus simazine or asulam. The MW distributions of a groundwater NOM were altered by coagulation and ultrafiltration, which resulted in the preferential removal of high-MW, UV260-absorbing NOM. At a given NOM loading, the simazine removal efficiency was higher in the column that was preloaded with raw groundwater than in columns receiving coagulated or ultrafiltered water. In contrast, the asulam removal efficiency was similar for all three NOM solutions at a given NOM loading. Therefore, the results suggested that low-MW, UV260-absorbing NOM molecules competed directly with strongly adsorbing pesticides, such as simazine, for adsorption sites. For more weakly adsorbing pesticides, such as asulam, direct competition for adsorption sites originated not only from the strongly adsorbing, low-MW NOM, but also from more weakly adsorbing, higher-MW NOM. Consequently, the competing NOM fraction increases as the adsorbability of the SOC decreases, a result that was confirmed by adsorption data for additional pesticides of similar size. However, a smaller pesticide competed more effectively for adsorption sites than a larger pesticide of similar polarity, suggesting that the concentration of competing NOM decreases as the MW of the SOC decreases.     

Genetic variation in the conservative gene region of Norovirus genogroup II strains in environmental and stool samples

Noroviruses (NoVs) have been one of leading etiological agents for infectious gastroenteritis over the world. Gastroenteritis caused by NoVs is prevalent in winter season, and the contamination of the water environment with NoVs in the epidemic cold season is frequently reported. In contrast, the number of gastroenteritis patients and NoVs in the water environment are reduced during the nonepidemic summer season, and the year-round fate of NoVs has remained to be elucidated. In this study, we collected nucleotide sequences of NoV genogroup II (GII) from domestic sewage, sewage sludge, treated wastewater, river water, and stool samples of gastroenteritis patients in geographically close areas. Phylogenetic analysis of the obtained NoV gene revealed that six out of seven isolates from environmental samples and 10 out of 11 isolates from stool samples belong to genotype 3 (NoV GII.3) or 4 (NoV GII.4), which have been prevalent throughout the world. Genetic distances between the conservative gene region of NoV GII.4 variants implied that genetically diverse strains are likelyto occur in environmental samples. The evaluation of the evolutionary change of NoV gene obtained from environmental samples would make it possible to elucidate the year-round fate of NoVs.     

Urinary trypsin inhibitor reduces inflammatory response in kidney induced by lipopolysaccharide

Human urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used in Japan as a drug for patients with acute inflammatory disorders such as septic shock and pancreatitis. Lipopolysaccharide (LPS) triggers the sepsis syndrome by activating monocytes to produce proinflammatory cytokines, including tumor necrosis factor alpha (TNFalpha), which potently stimulate the activation of neutrophils. The inhibitory mechanism of UTI on the systemic inflammatory response induced by the intraperitoneal injection of LPS in the kidney is unclear. This study was undertaken to examine the inhibitory effects of UTI on renal injury associated with the systemic inflammatory response induced by LPS stimulation, with emphasis on systemic TNFalpha and the activation of neutrophils in rat kidney. The systemic inflammatory response syndrome was induced by LPS treatment. Serum and renal TNFalpha, renal cytokine-induced neutrophil chemoattractant-1 (CINC-1) and myeloperoxidase (MPO) levels, as well as renal function after LPS stimulation, were evaluated. UTI (50,000 U/kg) inhibited LPS-induced increases in the serum and renal tissue levels of TNFalpha, as well as the renal tissue levels of CINC-1 and MPO after LPS stimulation. UTI (50,000 U/kg) also inhibited the production of serum TNFalpha associated with the systemic inflammatory response syndrome induced by LPS stimulation, thereby attenuating neutrophil infiltration into renal tissues and subsequent neutrophil-mediated renal injury. These findings may have important implications in understanding the biologic functions of UTI. UTI may prove useful in protecting against acute renal injury associated with a systemic inflammatory response.     

Carbon Nitride Loaded with an Ultrafine,Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO₃ and BaLa₄Ti₄O₁₅.