Search

Aerial observations of atmospheric pollutants were made over the East China Sea to analyze the transport of air pollutants, especially nitrogen oxides, from East Asia. Three flights each were conducted in October 2009 (autumn) and December 2010 (winter). Onboard measurements of gaseous total odd nitrogen species, gaseous nitric acid (HNO3(g)), O3, SO2, CO and black carbon were made and particles were collected on filters for ionic and metal component analyses. The NO3−(p)/T.NO3 (T.NO3 = HNO3(g) + NO3−(p); NO3−(p) indicates particulate nitrate) ratios were less than 0.5 in most cases. Exceptions were 17 October and 11 December, when high concentrations of dust particles (Kosa) were transported. The average T.NO3/NOy (NOy indicates total odd nitrogen species) ratio in winter was 0.59, and that in autumn was 0.71. In addition, positive and negative correlations between NOy − T.NO3 and ozone were observed in autumn and winter, respectively. These results indicate that the main components of NOy − T.NO3 are NOx and its descendant photochemical products, such as peroxyacyl nitrates and alkyl nitrates, in winter and autumn, respectively. Ratios of Na+ to Cl− + NO3− in particles were close to the seawater ratio for observations in both autumn and winter, save for the Kosa events. The main NO3−(p) formation process was the reaction of HNO3(g) with sea salt aerosols during autumn and winter. On the other hand, NO3−(p) was generated by the reaction of HNO3(g) with dust particles and sea salt during the Kosa events. The fraction of NH4NO3 in NO3−(p) was very small.

We conducted continuous measurements of NOy and total nitrate (T.NO3 = HNO3 + NO 3 − ( p ) ) at Fukue Island, Nagasaki, and Cape Hedo, Okinawa, Japan. We compared variations of NOy or T.NO3 concentrations measured at two remote sites when the air masses were originated from the same regions of the Asian Continent. Long-range transport events from the Asian Continent were extracted by CO concentration peaks at Fukue and Hedo and backward trajectory analyses. We compared the transport time difference at two sites from the Asian continent with the ratios of NOy at Hedo to that at Fukue (=R(NOy)) to find the predominant factor in NOy removal. R(NOy) were less than unity and decreased with the transport time difference. The ratios of NOy/CO at Hedo to those at Fukue (R(NOy/CO)) was assumed to be affected by the deposition process. R(NOy/CO) showed negative correlation with transport time difference as the same the case of R(NOy). This indicates that NOy was mainly removed by deposition rather than dilution. Air mass ages were classified by the ratio of T.NO3 to NOy at Fukue: T.NO3/NOy

The conformation of tridecapeptide alpha-mating factor from yeast Saccharomyces cerevisiae in aqueous solution was analyzed, in comparison with those of active analog and inactive analog peptides. 270-MHz 1H-NMR spectra of these peptides were observed and the spectral patterns of main-chain N-H proton resonances were classified into three groups. alpha-mating factor and Trp1-bearing active peptides belong to the group A1, active des-Trp1-peptides belong to the group A2 while the peptides of group B are inactive. The main-chain N-H proton resonances of the groups A1 and A2 and side-chain N-H proton resonances were all assigned to individual residues. The 13C-NMR analysis of alpha-mating factor indicates that the Lys7-Pro8 and Gln10-Pro11 peptide bonds exclusively take the trans form. From the temperature and pH dependences of chemical shifts and Gd(III)-induced relaxation enhancements of amide proton resonances, alpha-mating factor is found to take partly a folded conformation in aqueous solution, with an alpha-helical form in the N-terminal domain and two beta-turn forms in the central and C-terminal domain. The pH dependence of fluorescence intensity indicates that, in this folded conformation, the C-terminal carboxylate group lies close to the N-terminal domain. The presence of the folded form in the N-terminal domain and the beta-turn form in the central domain correlates with the biological activity of alpha-mating factor and analog peptides. However, the folded conformation of alpha-mating factor is in equilibrium with predominantly unordered form, as found from the circular dichroism and NMR analyses. The N-H proton and C-alpha proton resonances of free alpha-mating factor as assigned in the present study allow the transferred nuclear Overhauser enhancement (NOE) analysis of the membrane-bound conformation that is more directly related with the activity.