Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids

We predict a new mechanism to induce collective excitations of a fermionic superfluid via sudden switch-on of two-body loss, for which we extend the BCS theory to fully incorporate quantum jumps. We find that such dissipation induces an amplitude oscillation of the superfluid order parameter accompanied by chirped phase rotation, which highlights the role of dissipation in a superfluid as a consequence of particle loss. We demonstrate that when the dissipation is introduced to one of the two superfluids coupled via a Josephson junction, it gives rise to a relative-phase mode analogous to the Leggett mode, which can be detected from time evolution of the Josephson current. We find that the coupled system exhibits a nonequilibrium dissipative phase transition characterized by the vanishing dc Josephson current. The dissipation-induced collective modes can be realized with ultracold fermionic atoms undergoing inelastic collisions.Comment: 13 pages, 7 figure

Fibroblast growth factor 10 regulates Meckel's cartilage formation during early mandibular morphogenesis in rats

AbstractFibroblast growth factors (FGF) are pluripotent growth factors that play pivotal roles in the development of various organs. During mandibular organogenesis, Meckel's cartilage, teeth, and mandibular bone differentiate under the control of various FGF. In the present study, we evaluated the role of FGF10 in rat mandibular chondrogenesis and morphogenesis using mandibular organ culture and mandibular cell micromass culture systems. The overexpression of Fgf10 induced by the electroporation of an FGF10 expression vector not only altered the size and shape of Meckel's cartilage, but also upregulated the expression of the cartilage characteristic genes Col2a1 and Sox9 in a mandibular organ culture system. Meckel's cartilage was deformed, and its size was increased when Fgf10 was overexpressed in the lateral area of the mandible. Meanwhile, no effect was found when Fgf10 was overexpressed in the medial portion. In the mandibular cell micromass culture, recombinant FGF10 treatment enhanced chondrogenic differentiation and endogenous ERK (extracellular signal-regulated kinase) phosphorylation in cells derived from the lateral area of the mandible. On the other hand, FGF10 did not have significant effects on mandibular cell proliferation. These results indicate that FGF10 regulates Meckel's cartilage formation during early mandibular morphogenesis by controlling the cell differentiation in the lateral area of the mandibular process in rats

Structural Transformation of Tungsten-Zirconium Hydroxide Crystals Upon Calcination Characterized by XRD, XAFS and Acid Catalyzed Reaction

W：Zr 比が2：1 の二元系水酸化物を水熱合成法にて調製し，水熱処理の保持時間および焼成温度の異なる物質の構造をX 線回折，X 線吸収分光法で検討し，酸触媒特性を評価した．453 K での水熱処理では12 時間までは高表面積かつ結晶性の低い化学種（I 相）が生じ，24 時間以降で結晶性の高い水和物（ZWOH 結晶）が得られた．ZWOH 結晶は573−773K で結晶性の低いZrW2O8 多形（II 相），823−873K で立方晶ZrW2O8 へ変化することをX 線分析，UV-Vis 分光法および熱重量分析で確認した．I 相はアニソールのベンジルアルコールによるアルキル化を促進する固体強酸触媒として機能し，873K 焼成体が最高活性を示した．ZWOH 結晶およびZrW2O8 はアルキル化活性を示さなかった．立方晶系ZrW2O8 の結晶性の低いI 相が混在しても通常のXRD 解析では検出困難であるが，表面積測定および活性試験を併用すると混在の推定が可能であった．Tungsten zirconium hydroxides (ZWOH) with the molar ratio of W/Zr =2 were synthesized by a hydrothermal process at 453 K for 6-72 h. Structure of the hydroxides with different crystallinity and the transformation upon calcination were characterized by XRD, XAFS, UV-vis spectroscopic techniques. The ill-crystallized ZWOH with large surface area (>100m2 ·g−1; phase-I) was formed via hydrothermal treatment till 12 h, and well crystallized ZrW2O7(OH)2(H2O)2 (< 2 m2 ·g−1; c-ZWOH) was formed after 24 h. W L-edge XAFS, optical bandgap and thermal gravity analyses gave direct evidence to support the previous suggestion about dehydration process of c-ZWOH to ZrW2O8, where ZrW2O8 polymorphism with low crystallinity (phase-II) and cubic ZrW2O8 crystal formed after calcination in the range of 573−773 and 823−873 K, respectively. The ZWOH phase-I was found to promote alkylation of benzylalcohol with anisole, and the activity exhibited the maximum after calcination at 873 K. The c-ZWOH and ZrW2O8 polymorphisms were catalytically inert for the reaction. Existence of active phase-I as a minor species in ZrW2O8 little influence on XRD pattern, but surface area measurements and the catalytic performance might help to evaluate fraction of phase-I in the Zr-W-O system. The ZWOH phase-I was candidate for a model catalyst of tungstated zirconia strong solid acid to investigate the acidity generation mechanism