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An anomalously large dielectric permittivity of ≈10 is found in the mesophase temperature range (MP phase) wherein high fluidity is observed for a liquid-crystal compound having a 1,3-dioxane unit in the mesogenic core (DIO). In this temperature range, no sharp X-ray diffraction peak is observed at both small and wide Bragg angles, similar to that for a nematic phase; however, an inhomogeneous sandy texture or broken Schlieren one is observed via polarizing optical microscopy, unlike that for a conventional nematic phase. DIO exhibits polarization switching with a large polarization value, i.e., P = 4.4 µC cm , and a parallelogram-shaped polarization-electric field hysteresis loop in the MP phase. The inhomogeneously aligned DIO in the absence of an electric field adopts a uniform orientation along an applied electric field when field-induced polarization switching occurs. Furthermore, sufficiently larger second-harmonic generation is observed for DIO in the MP phase. Second-harmonic-generation interferometry clearly shows that the sense of polarization is inverted when the +/- sign of the applied electric field in MP is reversed. These results suggest that a unidirectional, ferroelectric-like parallel polar arrangement of the molecules is generated along the director in the MP phase.

A major problem with allergen-specific immunotherapy involving repeated injection of allergens is the risk of an anaphylactic reaction. We engineered the major house dust mite allergen, Der f 2, to reduce its capacity to induce skin test reactivity and histamine release from peripheral blood basophils in allergic patients. The engineered allergen, in which the disulfide bond that linked the N- and C-terminal sequences of Der f 2 was disrupted, retained T-cell epitopes essential for immunotherapy and ability to stimulate T-cell proliferation. Such engineered allergens are potentially useful for safer and more effective immunotherapy for allergies.

The deformation mechanism of “slide-ring” (SR) gels was investigated with small-angle neutron scattering (SANS). The SR gels were prepared by coupling α-cyclodextrin (CD) molecules on polyrotaxane chains consisting of poly(ethylene glycol) and CD. Because of a hollow structure of CD molecules, the cross-links made of CD molecules in a figure-of-eight shape can slide along the polymer chain. A normal butterfly pattern was observed for the first time in two-dimensional SANS isointensity profiles for the SR gels under uniaxial deformation, where the normal butterfly pattern means a prolate isointensity pattern in the direction perpendicular to the stretching direction. However, by either increasing the cross-link density or increasing the stretching ratio, the normal butterfly patterns changed to abnormal butterfly patterns as are commonly observed in conventional covalent-bonded chemical gels. The difference in the deformation mechanism as well as the cross-linking inhomogeneities between the SR gels and the covalent-bonded chemical gels is discussed by focusing on the unique architecture of the SR gels.