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Most organs scale proportionally with body size through regulation of individual cell size and/or cell number. Here we addressed how postmitotic and morphologically complex cells such as neurons scale with the body size by using the dendritic arbor of one Drosophila sensory neuron as an assay system. In small adults eclosed under a limited-nutrition condition, the wild-type neuron preserved the branching complexity of the arbor, but scaled down the entire arbor, making a "miniature". In contrast, mutant neurons for the Insulin/IGF signaling (IIS) or TORC1 pathway exhibited "undergrowth", which was characterized by decreases in both the branching complexity and the arbor size, despite a normal diet. These contrasting phenotypes hinted that a novel regulatory mechanism contributes to the dendritic scaling in wild-type neurons. Indeed, we isolated a mutation in the gene CHORD/morgana that uncoupled the neuron size and the body size: CHORD mutant neurons generated miniature dendritic arbors regardless of the body size. CHORD encodes an evolutionarily conserved co-chaperone of HSP90. Our results support the notion that dendritic growth and branching are controlled by partly separate mechanisms. The IIS/TORC1 pathways control both growth and branching to avert underdevelopment, whereas CHORD together with TORC2 realizes proportional scaling of the entire arbor., 体の大きさに合わせて神経細胞の大きさを制御するしくみを解明. 京都大学プレスリリース. 2014-03-17.

Magnetic susceptibility, magnetization process, specific heat, ultrasonic velocity, and inelastic neutron scattering experiments were performed on powdered and single-crystalline ${\mathrm{TmAu}}_{2}$ samples. ${\mathrm{TmAu}}_{2}$ with a simple body-centered tetragonal ${\mathrm{MoSi}}_{2}$-type structure undergoes a transition to an antiferromagnetic state at ${T}_{N}$ of 3.2 K. An anomaly at 7.0 K is observed in the temperature dependence of specific heat and magnetic susceptibility. A very large softening beyond 50% from 300 down to 7.0 K is also observed in the temperature dependence of the elastic constant of the ${C}_{11}\ensuremath{-}{C}_{12}$ mode. The results reveal clearly that the anomaly at 7.0 K ${(=T}_{Q})$ originates from a ferroquadrupolar ordering with an orthorhombic $\ensuremath{\gamma}$-symmetry-lowering mode. Separation between the ground and the first excited singlet states of $4f$ levels is so small in the quadrupolar ordered phase and a transition probability between these states is so extremely large that there occurs a Van Vleck antiferromagnetic transition at 3.2 K by exchange-induced magnetic moments arising from the transition between the ground and the first excited singlet states.

Position and content of hydrogen atoms in as-transported H x ZrNCl, which is the parent compound of a novel two-dimensional superconductor Li 0.16 ZrNCl with T c =15 K, are determined by powder neutron diffraction. Hydrogen atoms are found to occupy 6 c site with z =0.235, which is located between ZrN and Cl layers, and with an occupancy, g =0.4, i.e. x =0.4.