Fluoride complexation of element 104, rutherfordium

Fluoride complexation of element 104, rutherfordium (Rf), produced in the 248Cm(18O,5n)261Rf reaction has been studied by anion-exchange chromatography on an atom-at-a-time scale. The anion-exchange chromatographic behavior of Rf was investigated in 1.9-13.9 M hydrofluoric acid together with those of the group-4 elements Zr and Hf produced in the 18O-induced reactions on Ge and Gd targets, respectively. It was found that the adsorption behavior of Rf on anion-exchange resin is quite different from those of Zr and Hf, suggesting the influence of relativistic effects on the fluoride complexation of Rf.     

A new abietane and two dimeric abietane diterpenes from the black heartwood of Cryptomeria japonica

Three new diterpenes, sugikurojins A-C (1-3) were isolated from the black heartwood of Cryptomeria japonica. The structure of sugikurojin A was deduced to be 19-hydroxy-6,7-dehydroferruginol on the basis of extensive NMR experiments. Sugikurojin B was a dimer of 6,7-dihydroxyferruginol and 6,7-dehydroferruginol with a 6-O-11' linkage. Sugikurojin C was a dimeric ferruginol with 6-O-7' and 7-O-6' linkages. Also obtained in this investigation were the known compounds formosaninol (4), 15 sesquiterpenes (5-19), 16 diterpenes (20-35), three phenylpropanoids (36-38), and a phenolic compound (39).     

First synthesis of a series of core-modified tetrabenzoporphyrins

Successful synthesis of a series of highly conjugated porphyrin analogues, including thia-, dithia- and oxathia-tetrabenzoporphyrins, and their optical properties are reported.     

Photo-modification and synthesis of semiconductor nanocrystals

Both photo-oxidation and photosynthesis manifest a strong interaction between nanoparticles and photons due to the large surface area-to-volume ratio. The final sizes of the semiconductor nanocrystals are determined by the photon energy during these phenomena. The photosynthesis is demonstrated in a Si-rich oxide and is similar to thermal synthesis, which involves the decomposition of SiO_x into Si and SiO₂, that is well known and often employed to form Si or Ge nanocrystals embedded in SiO₂ by annealing SiO_x at high temperature. However, photosynthesis is much faster, and allows the low-temperature growth of Si nanocrystals and is found to be pronounced in the SiO nanopowder, which is made by thermal CVD using SiH₄ and O₂. The minimum laser power required for the photosynthesis in the SiO nanopowder is much lower than in the Si-rich oxide formed by the co-sputtering of Si and SiO₂. This is attributed to the weak bond strength of Si-Si and Si-O in the SiO nanopowder. Photosynthesis, which can control the size and position of Si nanocrystals, is a novel nanofabrication technique making the best use of the strong interaction between photons and nanoparticles.     

Iridoid glucosides from the fruit of Genipa americana

Four new iridoid glucosides, called genamesides A-D, have been isolated from the fruit of Genipa americana L. (Rubiaceae), along with four known iridoid glucosides, geniposidic acid, geniposide, gardenoside and genipin-gentiobioside. Their chemical structures were determined on the basis of spectroscopic data.     

Synthesis of methyl 1-O-(4-hydroxymethamphetaminyl)-alpha-D-glucopyranouronate

For the purpose of the direct characterization of the intact conjugated form in the urine of a methamphetamine (MA) abuser, 4-hydroxymethamphetamine (4-OHMA) glucuronate, corresponding to one of the metabolites of MA, was synthesized from the commercially available methyl 4-hydroxyphenylacetate.     

Crystal-to-crystal transformation from tri- to mononuclear Cu(II) complex with a sugar-derived ligand via proton transfer reaction and rearrangement of hydrogen bonding networks

Treatment of a glycosylamine derived Cu(II) complex with ethylamine resulted in crystal-to-crystal transformation from trinuclear complex [Cu3(L1)2(EtNH2)2(MeOH)2]x2MeOHxCHCl3 (2x2MeOHxCHCl3) to a dimeric structure of mononuclear complex [Cu(HL1)(EtNH2)] (3) through proton transfer reaction and rearrangement of hydrogen bonding networks.     

New CO tolerant electro-catalysts exceeding Pt-Ru for the anode of fuel cells

Novel types of CO tolerant electro-catalysts from Pt and organic metal complexes that are far superior to Pt-Ru and practically usable as anode catalysts in reformate gas fuel cells with 100 ppm CO tolerance have been developed.     

Spinorphin as an endogenous inhibitor of enkephalin-degrading enzymes: roles in pain and inflammation

It is possible that enkephalins are involved in the pain-modulating mechanism in the spinal cord. Enkephalins, however, are short-lived, being rapidly degraded by various endogenous enzymes. Many substances that inhibit enkephalin-degradation have been investigated and it has been reported that some inhibitors (e.g. kelatorphan and RB101) alone showed anti-nociceptive activity. We found an endogenous factor that modulated enkephalin-degrading activity and purified it from bovine spinal cord based on its inhibitory activity toward enkephalin-degrading enzymes. Structural analysis revealed the factor to be Leu-Val-Val-Tyr-Pro-Trp-Thr and it was named spinorphin. It has been found that spinorphin inhibited the activity toward various enkephalin-degrading enzymes from monkey brain, especially dipeptidyl peptidase III (DPPIII, Ki=5.1 x 10(-7) M). Recently we reported that this inhibitor significantly inhibited bradykinin (BK)-induced nociceptive flexor responses. Importantly, the mode of inhibition to BK-responses by spinorphin was different from the case with morphine. The morphine-induced blockade of BK-response was attenuated by pertussis toxin treatment, whereas that of spinorphin was not. We also have reported roles for spinorphin in inflammation. Spinorphin significantly inhibited the functions of polymorphonuclear neutrophils (PMNs) by suppressing the binding of fMLF to its receptor on PMNs. Further, this inhibitor suppressed the carrageenan-induced accumulation of PMN in mouse air pouches after intravenous administration. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator. The possible role of spinorphin and its analog as regulators in pain and inflammation will be discussed.     

Local magnetic fields in the Mo layer of Mo/Fe multilayer

Using time-differential perturbed-angular-correlation technique, hyperfine fields at ⁹⁹Tc (←⁹⁹Mo) in the Mo layers in polyimide/Fe (10 nm)/[Mo (t _Mo)/Fe (2.0 nm)]₁₂₀, where t _Mo is in the range between 0.4 and 1.5 nm, were measured at room temperature. The values of the magnetic hyperfine field at the Mo/Fe interface were extracted. Its dependence on the Mo layer thickness suggests that the oscillatory interlayer exchange coupling is due to conduction electron spin polarization in the Mo layer, which in turn is produced via an RKKY-type mechanism.