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The role of 4-hydroxyproline (Hyp) in stabilizing collagen triple helical structure has been investigated comprehensively. Recently it was emphasized that the preferential pyrrolidine ring pucker influenced by the stereoelectronic effects of substituted groups mainly affects the thermal stability of the triple helix. To examine this explanation, we synthesized and characterized (fProR-Pro-Gly)10and (fProS-Pro-Gly)10. According to the results of CD and analytical ultracentrifugation, (fProS-Pro-Gly)10takes a triple helical structure and (fProR-Pro-Gly)10exists in a single chain structure, the trend of which is not consistent with the relationship between (HypS-Pro-Gly)10and (HypR-Pro-Gly)10. In order to rationalize experimental results as a whole, we carried out DSC analyses and determined the thermodynamic parameters associated with the structural transition of these collagen model peptides. In this paper, we reported the DSC results for (Pro-Pro-Gly)10, (Pro-HypR-Gly)10and (Pro-fProR-Gly)10as a part of this study. Based on those parameters, we concluded that Hyp and fPro stabilize the triple helix in different stabilizing mechanisms; the increased stability of (Pro-HypR-Gly)10is ascribed primarily to the enthalpic effects while that of (Pro-fProR-Gly)10is achieved through the entropic ones.

A method for measuring magnetostriction constants ?100and ?111was developed for (111)-oriented polycrystalline films. Magnetostriction constants were estimated from the magnetic anisotropy induced by the application of in-plane uniaxial strain. In sputtered Pd100-xCoxalloy films, the estimated magnetostriction constants agree with those of PdCo single-crystal alloys. The magnetostriction constants of Pd/Co multilayered films (MLs), with decreasing bilayer period D, approach those of alloy with the same constitution, while with increasing D, they approach the values for fcc-Co obtained from the extrapolation of the data for the alloy films. These results are explained by the effect of electron hybridization and/or alloy formation at the interface of Pd and Co.

Fe/CoZr multilayer films prepared by the RF magnetron sputtering method are reported. The films have a bcc structure with the (110) preferred orientation and consist of fine crystallites of about 10 nm in diameter. The growth of crystallites is very gradual below 350°C. Even after annealing at 450°C, the grain growth is unremarkable, and compositionally modulated structure still remains. The films show excellent soft magnetic properties after annealing above 400°C. Typical values of saturation magnetization, coercive force and saturation magnetostriction were about 21 kG, 1.8 Oe, and +2×10-5, respectively. The films also show a high permeability of about 1800 at frequencies up to 100 MHz.

The giant magnetoresistance effect of Fe16Ni66Co18/Cu multilayers prepared by the RF magnetron sputtering method is reported. A magnetoresistance ratio as large as 35% is obtained at 300 K, and it oscillates as a function of Cu layer thickness. The oscillation period is about 1 nm, which is similar to the case of Co/Cu multilayers. The maximum interlayer coupling strength for the first peak is about 0.05 erg/cm2. For the second peak the coupling is as weak as 0.003 erg/cm2with a magnetoresistance ratio of 13%.

Magneto-optical Kerr loops and their energy spectra have been measured for ultrathin Co films sandwiched between Au layers. Polar Kerr hysteresis loops were detected for Co layer thicknesses down to 3 Å, showing complete squareness between 5 Å and 8 Å. When the Co layer is thicker than 20 Å, the spectral shape of the Kerr rotation, as well as the Kerr ellipticity, in an energy range of 1.5?5 eV agrees well with those calculated from bulk data. With decreasing Co thickness below 10 Å, the spectra become gradually smaller in magnitude than and different in shape from calculated ones.

Quenched high-temperature-phase MnBi film was successfully obtained by quenching the low-temperature-phase MnBi film in air. The high-temperature-phase has been found to appear below 300°C, which is different from a previously reported result. Its Kerr rotation and Kerr ellipticity spectra have been measured at room temperature, and are very different from that of the low-temperature-phase MnBi film in both magnitude and spectral structure.