nescence changes from blue to yellow after grinding. Like other such compounds, its original lumi-nescent state is restored upon dissolution and recrystallization, and this process could be repeated for 20 cycles without any decrease in luminescence. Structural and spectroscopic studies indicate that the long-lived blue emission in the crystal is intramolecular in origin and phos-phorescent (a localized intraligand π-π* transition), whereas the yellow emission appears to arise from an amorphous phase characterized by aurophilic interactions: intermolecular interactions between gold atoms.-PDS

Gold hydride is a rare transition-metal species. Despite the fact that gold hydrides may be key intermediates in several gold-catalyzed reactions, their chemical properties are not well understood. We report the synthesis, characterization, and catalytic properties of the gold(I) hydride species that play an important role in a gold(I)-catalyzed dehydrogenative alcohol silylation. Tricoordinated complexes AuCl(xantphos) (1a) and AuCl(xy-xantphos) (1b) were prepared and characterized by 1 H and 31 P{ 1 H} NMR measurements and X-ray crystallography. Gold(I) hydride species 6b generated from the reaction between 1b and PhMe 2 SiH (4b) in CDCl 3 was characterized by 1 H and 31 P NMR measurements and ESI-MS spectrometry. NMR and kinetic studies revealed that the reaction mechanism involves the gold(I) hydride species as a key intermediate. The high catalytic activities of 1a and 1b in dehydrogenative alcohol silylation are explained by the stability of the tricoordinated chelating structure and the activation of the Au-Cl bond induced by the stereoelectronic effect of the coordinating phosphorus atoms. This study reports the first example of a gold(I) hydride complex that exhibits catalytic activity.

Formation behavior of lipid nanoparticles (LNPs) in microfluidic devices with a staggered herringbone micromixer (SHM) structure was investigated. The fundamental role for SHMs in LNP formation was demonstrated by determining such factors as the limiting SHM cycle numbers and the effect of flow rate. The SHM cycle numbers and the position of the first SHM were as significant as factors as the flow rate condition for producing the small-size LNPs

The objective of this study was to predict R(b) (blood/plasma ratio) in humans using a simple method. Human and rat R(b) and free fraction in plasma (f(p)) values were obtained from the literature. The ratio of total red blood cell concentration to the free concentration in plasma (K(b)) was calculated using f(p) and R(b). Four methods were used for the prediction of R(b): (A) use of rat R(b); (B) use of R(b) calculated from rat K(b) and human f(p); (C) correlation of human log ((1-f(p))/f(p)) and human log K(b); and (D) correlation of log D with human log K(b). The R(b) of 96 compounds in humans ranged from 0.52 to 2.00, with an average of 0.89. A significant correlation was observed among human log K(b), human log ((1-f(p))/f(p)), and log D; however, no obvious correlation was observed among human R(b), human log ((1-f(p))/f(p)), and log D. The errors within 1.25-fold for methods A-D were 68.3%, 77.6%, 61.5% and 64.8%, respectively. All predictive methods considered here were superior to the use of the average value of human R(b) or R(b)=1. Rat R(b) corrected by human f(p) improved the accuracy of the prediction. Method B was the most accurate of the four methods.

Abstract. To clarify the biological processing of nitrate within temperate forested catchments using unprocessed atmospheric nitrate exported from each catchment as a tracer, we continuously monitored stream nitrate concentrations and stable isotopic compositions, including 17O excess (Δ17O), in three forested catchments in Japan (KJ, IJ1, and IJ2) for more than 2 years. The catchments showed varying flux-weighted average nitrate concentrations of 58.4, 24.4, and 17.1 µmol L−1 in KJ, IJ1, and IJ2, respectively, which correspond to varying export fluxes of nitrate: 76.4, 50.1, and 35.1 mmol m−2 in KJ, IJ1, and IJ2, respectively. In addition to stream nitrate, nitrate concentrations and stable isotopic compositions in soil water were determined for comparison in the most nitrate-enriched catchment (site KJ). While the 17O excess of nitrate in soil water showed significant seasonal variation, ranging from +0.1 ‰ to +5.7 ‰ in KJ, stream nitrate showed small variation, from +0.8 ‰ to +2.0 ‰ in KJ, +0.7 ‰ to +2.8 ‰ in IJ1, and +0.4 ‰ to +2.2 ‰ in IJ2. We conclude that the major source of stream nitrate in each forested catchment is groundwater nitrate. Additionally, the significant seasonal variation found in soil nitrate is buffered by the groundwater nitrate. The estimated annual export flux of unprocessed atmospheric nitrate accounted for 9.4 %±2.6 %, 6.5 %±1.8 %, and 2.6 %±0.6 % of the annual deposition flux of atmospheric nitrate in KJ, IJ1, and IJ2, respectively. The export flux of unprocessed atmospheric nitrate relative to the deposition flux showed a clear normal correlation with the flux-weighted average concentration of stream nitrate, indicating that reductions in the biological assimilation rates of nitrate in forested soils, rather than increased nitrification rates, are likely responsible for the elevated stream nitrate concentration, probably as a result of nitrogen saturation. The export flux of unprocessed atmospheric nitrate relative to the deposition flux in each forest ecosystem is applicable as an index for nitrogen saturation.

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