journal article

The interlayer space of clays is an interesting microenvironment to control the properties of included organic materials. In this study, chromic hybrid films consisting of synthetic saponite (SSA) and fluorescent organic molecules with planar p-conjugated systems were fabricated. The hybrid films exhibited reversible fluorescence color switching induced by swelling and drying, which caused the gallery height of SSA to change. Ultraviolet–visible absorption, steady-state and time-resolved fluorescence measurements of the hybrid films strongly suggested that the organic molecules formed an excimer in the swollen interlayer space of SSA, while they were a monomer in the dried interlayer space. The different emission wavelengths of the excimer and monomer resulted in the fluorescence color switching of the hybrid films. The reversibility of the color switching was maintained for at least 50 cycles with no change of fluorescence maxima. These chromic hybrid films represent a novel approach to obtain color switching.

Ferroelectrics have found a wide range of applications including memory elements, capacitors, and sensors. Molecular f erroelectric crystals have recently attracted growing interest as viable alternatives for conventional ceramic ferroelectrics, especially due to their non toxicity and solution processability. Herein, we show that a class of molecular compounds known as plastic crystals can exhibit ferroelectricity, provided that the constituent molecules are judiciously chosen from polar ionic molecules. The intrinsic features of plastic crystals, e.g. the rotational mot ion of molecules and phase transitions with lattice symmetry changes, provide the crystals with unique ferroelectric properties relative to conventional molecular crystals , i.e. the possibility to flexibly alter the direction of the polarization axis of a grown crystal by applying an electric field. Owing to t he tunability of the crystal orientation together with mechanical deformability, this novel type of molecular crystals represents an attractive functional material, which will undoubtedly find diverse applications.

A 78-year-old man underwent distal partial gastrectomy and Billroth I reconstruction for early gastric cancer in May 1995, then was followed up by us. In March 2005, he was found in upper gastrointestinal endoscopy to have an elevated Isp lesion of the duodenum. Histological examination of biopsy specimens showed on inflammatory polyp and no malignancy. After one year of observation, the lesion became a IIa+IIc lesion in upper gastrointestinal endoscopy. Biopsy specimens showed group V and suspected signet-ring cell carcinoma. After further examination, we conducted partial resection of the duodenum. Macroscopically, the 8×6 mm tumor appeared to be a IIa+IIc lesion located in the second portion of the duodenum. The histological diagnosis was signet-ring cell carcinoma, within the membrane, ly0 and v0. The surgical margin was negative. We conducted curative surgery. He is alive without recurrence almost 10years after the operation. Billroth I reconstruction enabled us to diagnose duodenal cancer early in this case.