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detects spontaneous polarization for BaTiO 3 . EBIC gain measured for V acc = 5 kV was 20, and steadily decreased as V acc was increased. At V acc = 15 kV, the EBIC gain decreased to 5.Further experiments were carried out on LiTaO 3 thin films. The LiTaO 3 film was prepared on n-Si(100) (7´10 17 cm ±3 P) by spin-casting the organic precursor [27] and subsequently annealing at 650 C for 1 h. The film was strongly (104) oriented. Figure 3 compares SE and LEEBIC images taken on a LiTaO 3 film without prior biasing. PTC measurements showed a low level of spontaneous polarization pointing inward to the substrate. The LEEBIC image, Figure 3b, shows an inhomogeneous film corresponding to poled and non-poled domains. The poled domains are white, matching theoretical predictions for current flow of an inward-poled film, and the EBIC gain was 5.These experimental results support the earlier theoretical derivations. Spontaneous polarization is detectable by LEEBIC and Figure 3b shows spatial resolution resulting from this technique. Variation of V acc results in depth alteration of heat deposition, and is a technique to map a thin film in layers.The presented LEEBIC mapping technique accurately detects the presence of spontaneous polarization in ferroelectric thin films. Since the electric field is induced by a temperature gradient, no external bias is necessary for carrier collection. Lateral resolution is determined by the thermal conductivity ratio of film to substrate and this technique is limited to materials with a sufficient pyroelectric coefficient. This method in conjunction with thermal wave spectroscopy can map three-dimensional images of spontaneous polarization.Although a rewritable paper is desirable in a future ªgreenº industrial society, it has not been realized until now. Recording materials for such a paper should satisfy criteria for reversibility, full-color recording, and persistency of information with zero power consumption. Recently, we reported a rewritable full-color recording material working in a thermal mode, where the cholesteric colors due to the periodic helical alignment of molecules of a non-polymeric cholesteric liquid crystal (CLC) were reversibly changed and fixed. [1,2] However, the material has always suffered from low speed and low resolution for recording, the latter problem being intrinsic to thermal recording. We now introduce a reversible full-color recording material working in a photon mode, which is able to record images by a photochemically initiated reaction. The different colors are fixed by changing the amount of ultraviolet (UV) light exposure of a non-polymeric CLC film containing a small amount of an azobenzene derivative that undergoes cis±trans isomerization upon irradiation. In this system, the photochemical isomerization of an azobenzene derivative reversibly induces the change in the helical pitch (cholesteric color) of the CLC above 87 C. No change in the helical pitch occurs photochemically or thermally at room temperature in the cholesteric solid state obtained ...

To evaluate the mechanism of the development of therapeutic resistance after temozolomide treatment, we focused on changes in O(6)-methylguanine DNA methyltransferase (MGMT) and mismatch repair (MMR) between initial and recurrent glioblastomas. Tissue samples obtained from 24 paired histologically confirmed initial and recurrent adult glioblastoma patients who were initially treated with temozolomide were used for MGMT and MMR gene promoter methylation status and protein expression analysis using methylation-specific multiplex ligation probe amplification (MS-MLPA), methylation-specific polymerase chain reaction (MSP), and immunohistochemical staining. There was a significant decrease in the methylation ratio of the MGMT promoter determined by MS-MLPA, which was not detectable with MSP, and MGMT protein expression changes were not remarkable. However, there was no epigenetic variability in MMR genes, and a relatively homogeneous expression of MMR proteins was observed in initial and recurrent tumors. We conclude that the development of reduced methylation in the MGMT promoter is one of the mechanisms for acquiring therapeutic resistance after temozolomide treatment in glioblastomas.