Oxygen K-edge X-ray absorption near edge structures (XANES) of sublimated films of amino acids.

Oxygen K-edge X-ray absorption near edge structures (XANES) spectra of amino acids (glycine, L-alpha-alanine, beta-alanine, L-serine, L-asparic acid and L-tyrosine) were measured. Several peaks of XANES spectra were successfully assigned on the basis of DV-Xalpha calculation.

XAS and MCD studies in Eu0.6Sr0.4MnO3.

Eu(1-x)Sr(x)MnO3 system is one of the perovskite manganites that exhibit the giant magneto resistance effect and the transition from the insulator phase to the metal. Eu(0.6)Sr(0.4)MnO3 behaves as a ferromagnetic semiconductor and has an Insulator-Metal (IM) transition induced by external magnetic field, which could be found only in this system among the perovskite manganites group. The mechanism of the transition was investigated by X-ray Magnetic Circular Dichroism (XMCD) at the Mn L2,3-edges of and the Eu M4,5-edges in Eu(0.6)Sr(0.4)MnO3.

A grating monochromator of BL23SU at SPring-8 covering silicon and oxygen K-edges.

We report the present performance of a grating monochromator at the newly constructed soft x-ray beamline (BL23SU at the SPring-8), which can measure both silicon and oxygen K-edges. That provides new opportunities for XAFS measurements of solids up to 2100 eV.

Soft x-ray absorption spectra of ilmenite family.

We have carried out soft x-ray absorption spectroscopy to study the electronic structure of ilmenite family, such as MnTiO3, FeTiO3, and CoTiO3 at the soft x-ray beamline, BL23SU, at the SPring-8. The Ti and M L2,3 absorption spectra of MTiO3 (M=Mn, Fe, and Co) show spectra of Ti4+ and M2+ electron configurations, respectively. Except the Fe L2,3 spectrum, those spectra were understood within the O(h) symmetry around the transition metal ions. The Fe L3-edge spectrum clearly shows a doublet peak at the L3 edge, which is attributed to Fe2+ state, moreover the very high-resolution the L-edge spectra of transition metals show fine structures. The spectra of those ilmenites are compared.

Relaxation process of the excited state and selection rule in the soft X-ray emission of Si and cBN.

The soft X-ray emission spectra of Si and cubic boron nitride (cBN) are compared in the Si2p- and B1s-core exciton regions because inversion symmetry is lost and the band gap is extremely large for cBN although both crystal structures are very similar. The background in the soft X-ray emission spectrum of Si is much larger than that for cBN but becomes extremely weak as the excitation energy becomes low and the Raman process becomes dominant compared with the fluorescence process. The background is found to be mainly formed by electron excitation from the valence band to the conduction band. The Raman spectrum is similar to the absorption spectrum in cBN, while those of Si are quite different from each other. It is shown that the centrosymmetry is important in the selection rule of Raman scattering. In resonant Raman scattering the selection rule partly breaks down due to the lattice relaxation process that emits an ungerade phonon in the intermediate state.

[Enzymeimmunoassay of human interferon-alpha using monoclonal antibody].

Five monoclonal antibodies to human rIFN-alpha A have been obtained and used them in a sandwich enzymeimmunoassay for IFN-alpha. In the assay, rIFN-alpha A was measured from approximately 100 U/ml to 1,000 U/ml, but the sensitivity and the extent to measurement were different among using monoclonal antibodies. Protease or heat denatured IFN-alpha could not be detected in the enzymeimmunoassay and thus only a biologically active form of IFN-alpha was measurable. The reproducibility of the enzymeimmunoassay was considerably high (variation coefficient was lower than 10%) and the correlation of IFN-alpha titers with CPE method was observed slightly. Although the same CPE titers, natural IFN-alpha was detected only 20% compared with rIFN-alpha A in the enzymeimmunoassay, so the assay system seemed to be very specific for rIFN-alpha A. From this observation, it was suggested that the monoclonal antibodies used in the enzymeimmunoassay should recognize a epitope specifically existed on the rIFN-alpha A molecule.

[Test production and clinical use of human leukocyte interferon in Hokkaido Red Cross Blood Center].

Since 1979, we have studied to establish large scale production of HU IFN by buffy coat collecting from blood donor. Up to the present, we produced HU IFN of 71.5 X 10(8) units and used clinically for 40 patients. Recently, we reported the process of HU IFN production and the result of clinical use by members of Hokkaido Interferon Research.