Type-I clathrate compounds have attracted a great deal of interest in connection with the search for efficient thermoelectric materials. These compounds constitute networked cages consisting of nano-scale tetrakaidecahedrons (14 hedrons) and dodecahedrons (12 hedrons), in which the group 1 or 2 elements in the periodic table are encaged as the so-called "rattling" guest atom. It is remarkable that, though these compounds have crystalline cubic-structure, they exhibit glasslike phonon thermal conductivity over the whole temperature range depending on the states of rattling guest atoms in the tetrakaidecahedron. In addition, these compounds show unusual glass-like specific heats and THz-frequency phonon dynamics, providing a remarkable broad peak almost identical to those observed in topologically disordered amorphous materials or structural glasses, the so-called Boson peak. An efficient thermoelectric effect is realized in compounds showing these glass-like characteristics. This decade, a number of experimental works dealing with type-I clathrate compounds have been published. These are diffraction experiments, thermal and spectroscopic experiments in addition to those based on heat and electronic transport. These form the raw materials for this article based on advances this decade. The subject of this article involves interesting phenomena from the viewpoint of not only physics but also from the view point of the practical problem of elaborating efficient thermoelectric materials. This review presents a survey of a wide range of experimental investigations of type-I clathrate compounds, together with a review of theoretical interpretations of the peculiar thermal and dynamic properties observed in these materials.

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SUMMARY Histone modifications regulate chromatin-dependent processes, yet the mechanisms by which they contribute to specific outcomes remain unclear. H3K4me3 is a prominent histone mark that is associated with active genes and promotes transcription through interactions with effector proteins that include initiation factor TFIID. We demonstrate that H3K4me3-TAF3 interactions direct global TFIID recruitment to active genes, some of which are p53 targets. Further analyses show that (i) H3K4me3 enhances p53-dependent transcription by stimulating preinitiation complex (PIC) formation; (ii) H3K4me3, through TAF3 interactions, can act either independently or cooperatively with the TATA box to direct PIC formation and transcription; and (iii) H3K4me3-TAF3/TFIID interactions regulate gene-selective functions of p53 in response to genotoxic stress. Our findings indicate a mechanism by which H3K4me3 directs PIC assembly for the rapid induction of specific p53 target genes.