The elastic properties of a filled skutterudite PrOs 4 Sb 12 with a heavy fermion superconductivity at T C ϭ1.85 K have been investigated. The elastic softening of (C 11 ϪC 12 )/2 and C 44 with lowering temperature down to T C indicates that the quadrupolar fluctuation due to the CEF state plays a role for the Cooper paring in superconducting phase of PrOs 4 Sb 12 . A Debye-type dispersion in the elastic constants around 30 K revealed a thermally activated ⌫ 23 rattling due to the off-center Pr-atom motion obeying ϭ 0 exp(E/k B T) with an attempt time 0 ϭ8.8ϫ10 Ϫ11 s and an activation energy Eϭ168 K. It is remarkable that the charge fluctuation of the off-center motion with ⌫ 23 symmetry may mix with the quadrupolar fluctuation and enhance the elastic softening of (C 11 ϪC 12 )/2 just above T C .The rare-earth cubic compounds based on Pr 3ϩ ions have received much attention because various unusual properties are expected at low temperatures. The system with a non-ϪJ y 2 favors a quadrupole ordering. We refer the ⌫ 3 ground state systems as a metallic compound PrPb 3 showing the antiferro-quadrupole ordering at T Q ϭ0.4 K 1 and a semiconductor PrPtBi undergoing ferroquadrupole ordering at T Q ϭ1.2 K. 2 PrSb is known as a singlet ground state system. 3 The elastic constant (C 11 ϪC 12 )/2 is responsible for the quadrupolar susceptibility of O 2 0 and O 2 2 with ⌫ 3 symmetry, while C 44 is for the susceptibility of O yz ϭJ y J z ϩJ z J y , O zx ϭJ z J x ϩJ x J z , O xy ϭJ x J y ϩJ y J x with ⌫ 5 symmetry. The softening of (C 11 ϪC 12 )/2 and C 44 is useful proof to clarify the quadrupolar effects of Pr-based compounds.Recently, Bauer et al. have found a new-type of the heavy-fermion superconductor in a filled skutterudite PrOs 4 Sb 12 with space group T h 5 (Im3). 4 The heavy fermion state with a large specific heat coefficient ␥ϭ750 mJ/mol K 2 of PrOs 4 Sb 12 exhibits the superconducting transition at T C ϭ1.85 K associated with a large jump ⌬C/T C ϳ500 mJ/mol K 2 . A sign of the double transition in the specific heat has been found. 5 The thermal transport measurement in fields suggests the two distinct superconducting phases in PrOs 4 Sb 12 . 6 The nuclear spin relaxation rate 1/T 1 of Sb indicates unconventional superconductivity possessing neither a coherence peak nor a T 3 -power law. 7 The muon spin relaxation in PrOs 4 Sb 12 yields a penetration depth indicating a new type of energy gap. 8 The odd-parity Cooper pairing mediated by the quadrupole fluctuation is argued as unconventional heavy-fermion superconductivity in PrOs 4 Sb 12 . 9 Because the magnetic susceptibility is rather silent to distinguish non-magnetic ⌫ 23 doublet from ⌫ 1 singlet, it has not been settled whether the CEF ground state of PrOs 4 Sb 12 is ⌫ 23 doublet or ⌫ 1 singlet. 4,10 The measurement of (C 11 ϪC 12 )/2 and C 44 responsible for the quadrupolar sus-ceptibility in PrOs 4 Sb 12 is a central issue to clarify the CEF state and the interplay of the quadrupolar fluctuation to the superconductivity in PrOs 4 Sb 12 .

In vitro fabrication of vascularized three-dimensional (3D) human cardiomyocyte (CM) tissues derived from human induced pluripotent stem cells (iPSCs) has attracted much attention owing to their requirement of much amount of nutrition and oxygen, but not yet published. In this manuscript, we report construction of vascularized 3D-iPSC-CM tissues by a newly-discovered filtration-Layer-by-Layer (LbL) technique. The filtration-LbL fabricates nanometer-sized fibronectin and gelatin (FN-G) films onto iPSC-CM surfaces. The FN-G nanofilms induce cell-cell interactions via integrin molecules on cell surfaces, leading to construction of 3D-tissues. The constructed vascularized 3D-iPSC-CM tissues would be a promising tool for tissue regeneration and drug development. We believe that this manuscript has a strong impact and offers important suggestions to researchers concerned with biomaterials and tissue engineering.

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During thunderstorms on 20 September 2008, a simultaneous detection of gamma rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 sec, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung gamma rays arriving from a source which is 60-130 m in distance at 90% confidence level. The observed electrons are likely to be dominated by a primary population escaping from an acceleration region in the clouds.

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