Robust anion exchange membranes based on ionic liquid grafted chitosan/polyvinyl alcohol/quaternary ammonium functionalized silica for polymer electrolyte membrane fuel cells.

In this study, 1-bromohexyl-1methylpiperidinium bromide (Br-6-MPRD) ionic liquid grafted quaternized chitosan (QCS) and polyvinyl alcohol (PVA) blends were composited with glycidyl trimethyl ammonium chloride (GTMAC) quaternized silica (QSiO2) at different dosages. Glutaraldehyde (GA) crosslinked the membranes and then processed into hydroxide form with an aqueous potassium hydroxide solution. The resultant IL-QCS/PVA/QSiO2 membranes exhibit significantly improved ionic conductivity, moderate water absorption and swelling ratio compared with the pristine IL-QCS/PVA anion exchange membrane (AEM). Among them, the hydroxide ion conductivity and power density of IL-QCS/PVA/QSiO2-7 membrane can reach up to 78 mS cm-1 at 80 °C and 115 mW cm-2 at 60 °C respectively. In addition, IL-QCS/PVA/QSiO2 membranes have excellent thermal, mechanical, and chemical stabilities, which can meet the application requirements of AEM for fuel cells.

N2O dynamics in the western Arctic Ocean during the summer of 2017.

The western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0-50 m) and deep layers (200-2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0-50 m) of the southern Chukchi Sea and the intermediate (50-200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 µmol N2O m-2 day-1), whereas the northern region acted as a sink (mean - 1.3 ± 1.5 µmol N2O m-2 day-1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O "hot spot", and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.

A Comprehensive Review of Recent Studies on Herb-Drug Interaction: A Focus on Pharmacodynamic Interaction.

OBJECTIVES: The concomitant use of herbal and conventional drugs accelerates the possibility of clinically significant herb-drug interactions (HDIs). This paper aims to analyze the current status of HDI studies worldwide and to review studies on HDI-induced pharmacodynamic (PD) interactions. METHODS: HDI studies published from 2000 to 2014 and indexed in PubMed were categorized according to publication year, area/country, study methods and objectives, and disease categories. The reviewed studies focused on HDI-induced PD; each PD interaction with concurrent use of approximately 100 herbal drugs and 70 conventional drugs was summarized. All PD-related articles were categorized according to four characteristics: herbal drugs, conventional drugs, types of PD interaction, and type of study. Among them, 17 well-designed clinical studies were evaluated by using the Jadad Quality Assessment Scale. RESULTS: The number of HDI reports has gradually increased since 2000, with a primary focus on neoplasms and diseases of the circulatory system. Most of these investigated pharmacokinetic reactions, such as cytochrome P450 enzyme metabolism, with fewer reports investigating PD. Most PD interaction studies investigated warfarin, ginkgo leaves, and St. John's wort. An evaluation of 17 studies revealed a generally positive view of PD effects involving synergism or reduced toxicity and a high average quality score (>3 points on a 0-5 scale). CONCLUSIONS: These results demonstrate that most HDI studies so far have examined PK interactions and have been limited to very few conventional drugs and herbal drugs. This suggests that more studies focusing on PD are necessary to understand interactions between commonly used herbal and conventional drugs.