Green tea polyphenol sensing

Green tea polyphenols have emerged over the past two decades as an important dietary factor for health promotion. There is considerable evidence that tea polyphenols, in particular (-)-epigallocatechin-3-gallate (EGCG) inhibit carcinogenesis. However, the mechanisms for the cancer-preventive activity of EGCG are not completely characterized and many features remain to be elucidated. Recently we have identified a cell-surface EGCG receptor and the relating molecules that confer EGCG responsiveness to many cancer cells at physiological concentrations. Here, we review some of the reported mechanisms for the cancer chemopreventive action of EGCG and provide an overview of several molecules that sense and manage the physiological functions of EGCG.     

Novel methodology to control the adsorption structure of cationic porphyrins on the clay surface using the "size-matching rule"

Saponite-type clays that have different cation exchange capacities were successfully synthesized by hydrothermal synthesis. The structure and properties were analyzed by X-ray diffraction, X-ray fluorescence, (27)Al NMR, FT-IR, thermogravimetric and differential thermal analysis, atomic force microscopy, and cation exchange capacity measurement. The intercharge distances on the synthetic saponite (SS) surfaces were calculated to be 0.8-1.9 nm on the basis of a hexagonal array. The complex formation behavior between SS and cationic porphyrins was examined. It turns out that the average intermolecular distance between porphyrin molecules on the SS surface can be controlled, depending on the charge density of the SS. In the case of tetrakis(1-methylpyridinium-4-yl)porphyrin (H(2)TMPyP(4+)), the average intermolecular distances on the SS surface can be controlled from 2.3 to 3.0 nm on the basis of a hexagonal array. It was also found that absorption maxima of porphyrins depend on the charge density of the SS. The adsorption behavior of porphyrin on the SS surface can be rationally understood by the previously reported "size-matching rule". This methodology using host-guest interaction can realize a unique adsorption structure control of the porphyrin molecule on the SS surface, where the gap distance between guest porphyrin molecules is rather large. These findings will be highly valuable to construct photochemical reaction systems such as energy transfer in the complexes.     

Synergistic inhibition of malignant melanoma proliferation by melphalan combined with ultrasound and microbubbles

The cavitational effects of ultrasound (US) exposure induce transient pores on the cell membrane (sonoporation). Sonoporation have been applied in the field of cancer therapy by promoting delivery of extracellular molecules such as drugs and genes into cytoplasm. In addition, it is known that using US together with microbubbles (MB) elevates permeability of these agents. In this study, by applying the US-MB strategy for melanoma chemotherapy, we evaluated the antitumor effect of melphalan combined with US-MB on a melanoma cell line (C32) in vitro and in vivo. The in vitro cytotoxic effect of the melphalan with US-MB was greater than that of melphalan alone or melphalan in combination with US. In vivo experiments using xenografts, intratumoral injection of melphalan and MB with US exposure led to a greater degree of tumor regression than did the intratumoral injection of the melphalan alone or melphalan in combination with US. These results suggest that US-MB promotes the antitumor effect of melphalan by increasing delivery of molecules into cells and that this strategy may become an effective method of adjuvant therapy against malignant melanoma.     

Andreev reflection between a normal metal and the FFLO superconductor

We consider a process of the Andreev reflection between a normal metal and the s-wave superconductor in the FFLO state. It is shown that the process takes place if the energy of the incoming electron is bound within the finite interval called the Andreev window. The position of the window determines the value of the non-zero total momentum of Cooper pairs and the value of the gap.     

ChemInform Abstract: Hydrogen Dissociative Chemisorption and Desorption on Saturated Subnano Palladium Clusters (Pdn,n = 2—9)

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