Sat, 26 Jul 2008 06:22:21 BST CiteULike: dchen's Matsushita http://www.citeulike.org/user/dchen/author/Matsushita CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2759188 <i>Physical Review Letters, Vol. 100, No. 16. (2008)</i><br /><br />Fluorescence spectroscopy of single proteins at liquid-helium temperatures reveals a relation between structural dynamics and biological functions of the proteins. The technical difficulties in detecting visible fluorescence are chromatic aberration and optical background. They were overcome by a new optical design using reflective optics and employing two-photon excitation. The fluorescence spectrum of single green-fluorescent proteins taken at a temperature of 1.5 K makes a distinction between different metastable conformations that last for tens of seconds. Visible Fluorescence Spectroscopy of Single Proteins at Liquid-Helium Temperature Satoru Fujiyoshi Masanori Fujiwara Michio Matsushita doi:10.1103/PhysRevLett.100.168101 Physical Review Letters, Vol. 100, No. 16. (2008) 2008-05-05T20:53:11-00:00 2008 Physical Review Letters 100 16 APS 2008 biology microscope protein structure technique http://www.citeulike.org/user/dchen/article/2754244 <i>Physical Review Letters, Vol. 98, No. 19. (2007)</i><br /><br />A mesoscopic tiling pattern with 12-fold symmetry has been observed in a three-component polymer system composed of polyisoprene, polystyrene, and poly(2-vinylpyridine) which forms a star-shaped terpolymer, and a polystyrene homopolymer blend. Transmission electron microscopy images reveal a nonperiodic tiling pattern covered with equilateral triangles and squares, their triangle/square number ratio of 2.3 (4/), and a microbeam x-ray diffraction pattern shows dodecagonal symmetry. The same kind of quasicrystalline structures have been found for metal alloys (~0.5 nm), chalcogenides (~2 nm), and liquid crystals (~10 nm). The present result (~50 nm) confirms the universal nature of dodecagonal quasicrystals over several hierarchical length scales. Polymeric Quasicrystal: Mesoscopic Quasicrystalline Tiling in ABC Star Polymers Kenichi Hayashida Tomonari Dotera Atsushi Takano Yushu Matsushita doi:10.1103/PhysRevLett.98.195502 Physical Review Letters, Vol. 98, No. 19. (2007) 2008-05-04T16:23:48-00:00 2007 Physical Review Letters 98 19 APS 2007 focus material optical polymer structure