Analysis of imazalil and its major metabolite in citrus fruits by GC-FTD

A simplified simultaneous analytical method of imazalil (IZ) and its major metabolite, alpha-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol (IZM), in citrus fruits was developed, and commodities samples were investigated. A homogenate of citrus fruits was extracted with ethyl acetate under basic conditions. The crude extract was partitioned between 0.025 mol/L of sulfuric acid and ethyl acetate. The analytes were extracted from the aqueous fraction under basic conditions with ethyl acetate. The extract solution was purified with an ENVI-Carb cartridge, and then analyzed by GC-FTD and GC/MS. Recoveries of IZ and IZM added to grapefruit at the level of 0.05 microgram/g were 90.0 and 108.7%, and those in the case of lemon were 100.4 and 93.0%, respectively. The detection limits were 0.01 microgram/g in samples. By this method, IZ and IZM were analyzed in 46 citrus fruits on the market and were detected simultaneously in some samples.     

Aspirin-triggered 15-epi-lipoxin A4 (ATL) generation by human leukocytes and murine peritonitis exudates: development of a specific 15-epi-LXA4 ELISA

Aspirin (ASA) triggers the formation of 15-epi-lipoxins (15-epi-LXs or ATL [ASA-triggered LX]), which are potent bioactive eicosanoids that may contribute to the therapeutic impact of ASA. To elucidate the role of these new compounds in vivo, it is essential to establish quick and sensitive detection methods. To this end, we prepared an enzyme-linked immunosorbent assay specific for 15-epi-LXA4 that proved to be highly sensitive (IC50 approximately 50 pg, minimum detection approximately 3.5 pg) and stereoselective. The amounts of 15-epi-LXA4 generated by human neutrophils from peripheral blood of healthy volunteers using this enzyme-linked immunosorbent assay were in agreement with those values obtained by liquid chromatography. Formation of 15-epi-LXA4 was cell ratio-dependent during THP-1 (a monocytic leukemia cell line)-neutrophil interactions with ASA-treated cells, and 15-epi-LXA4 was not detected with either cell type alone. Generation of 15-epi-LXA4 was also examined in murine peritonitis with ASA administration. Exudates from ASA-treated mice showed increased production of 15-epi-LXA4 that was diminished by indomethacin, a blocker of ASA-dependent acetylation of prostaglandin G/H synthase. A cytochrome P450 inhibitor administered in the presence of ASA did not prevent 15-epi-LXA4 formation, which suggests that P450 does not significantly contribute to formation of 15-epi-LXA4 in this murine model. These results indicate that the new enzyme-linked immunosorbent assay is both sensitive and selective for 15-epi-LXA4 and that 15-epi-LXA4 is produced by human leukocyte-leukocyte interactions. In addition, 15-epi-LXA4 is generated by inflammatory exudates when ASA is administered during murine peritonitis and when prostaglandin G/H synthase is upregulated and acetylated. This assay should provide rapid means to investigate 15-epi-LXA4 generation in both cellular and animal models.     

Preparation of a Gas Diffusion Electrode by Ozone Gas Pretreatment and an Ion-exchange Method

Surface oxidation using ozone gas, produced by an electrolytic ozone generator, was applied for preparation of a gas-diffusion electrode (GDE) for an electrochemical energy conversion system. An uncatalyzed carbon sheet containing poly(tetrafluoroethylene) binder was first placed into contact with ozone gas to form active functional groups on the surface of the carbon; then ion-exchange between a weakly bound hydrogen of the functional groups and a platinum cation complex was performed. A GDE having highly dispersed particles of a platinum metal deposited on a porous carbon sheet ws developed by this method. The fuel cell using this GDE showed high performance.     

Effects of boron doping in low- and high-surface-area carbon powders

Two distinctive carbon materials (Saran char and SP-1 graphite) were doped with B at different loading to clarify the intrinsic effect of substitutional B on carbon reactivity. The carbon precursors would be affected in different style by substitutional B due to different important properties (crystallinity and surface area). The B retentivity depended on the nature of B dopant and carbon substrate; a less ordered carbon has higher B loading than its counterpart. Graphitization was enhanced by substitutional B, as expected. Furthermore, the B incorporation was still beneficial for SP-1 although it already had high crystallinity. An interesting behavior was noticed; the increase in L_a was greater than L_c. The intrinsic effect of substitutional B in carbon oxidation was proved to be a catalytic one. Unlike highly ordered SP-1 graphite, Saran char showed both a catalytic effect at low B loading and low conversion, and an inhibiting effect at high B loading and high conversion. The inductive effect was proposed to explain this catalytic effect on different crystallite size. Different sizes of carbon clusters were calculated by Gaussian 98W; the extent of the effect of substitutional B did get smaller to the carbon in bigger size of carbon cluster.     

Chromium-Free Corrosion Resistance of Metals by Ceramic Coating

Metal surfaces can be improved in terms of thermal, mechanical, and chemical properties by a ceramic coating. The chromium-free corrosion resistance of stainless steel was achieved using a chemical solution method. Precursor solutions were prepared from metal alkoxides and were deposited on stainless-steel surfaces by dip coating and heat-treating at temperatures <500°C. The stainless steel was coated by silica, zirconia, and titania single-layer coating films, and/or coated by silica/zirconia and silica/titania double-layer coating films. The corrosion resistance was improved remarkably by a submicrometer silica-based coating on the stainless steel.