2,586 research outputs found

    2-[(3S)-5-Oxooxolan-3-yl]isoindoline-1,3-dione

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    The oxolan-2-one ring in the title compound, C12H9NO4, has an envelope conformation with the atom linking the two five-membered rings being the flap atom

    Evidence for Two Gaps and Breakdown of the Uemura Plot in Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 Single Crystals

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    We report a detailed investigation on the lower critical field Hc1H_{c1} of the superconducting Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 (FeAs-122) single crystals. A pronounced kink is observed on the Hc1(T)H_{c1}(T) curve, which is attributed to the existence of two superconducting gaps. By fitting the data Hc1(T)H_{c1}(T) to the two-gap BCS model in full temperature region, a small gap of Δa(0)=2.0±0.3\Delta_a(0)=2.0\pm 0.3 meV and a large gap of Δb(0)=8.9±0.4\Delta_b(0)=8.9\pm 0.4 meV are obtained. The in-plane penetration depth λab(0)\lambda_{ab}(0) is estimated to be 105 nm corresponding to a rather large superfluid density, which points to the breakdown of the Uemura plot in FeAs-122 superconductors.Comment: 5 pages, 4 figure

    Mesenchymal adenomatous polyposis coli plays critical and diverse roles in regulating lung development.

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    BackgroundAdenomatous polyposis coli (Apc) is a tumor suppressor that inhibits Wnt/Ctnnb1. Mutations of Apc will not only lead to familial adenomatous polyposis with associated epithelial lesions, but will also cause aggressive fibromatosis in mesenchymal cells. However, the roles of Apc in regulating mesenchymal cell biology and organogenesis during development are unknown.ResultsWe have specifically deleted the Apc gene in lung mesenchymal cells during early lung development in mice. Loss of Apc function resulted in immediate mesenchymal cell hyperproliferation through abnormal activation of Wnt/Ctnnb1, followed by a subsequent inhibition of cell proliferation due to cell cycle arrest at G0/G1, which was caused by a mechanism independent of Wnt/Ctnnb1. Meanwhile, abrogation of Apc also disrupted lung mesenchymal cell differentiation, including decreased airway and vascular smooth muscle cells, the presence of Sox9-positive mesenchymal cells in the peripheral lung, and excessive versican production. Moreover, lung epithelial branching morphogenesis was drastically inhibited due to disrupted Bmp4-Fgf10 morphogen production and regulation in surrounding lung mesenchyme. Lastly, lung mesenchyme-specific Apc conditional knockout also resulted in altered lung vasculogenesis and disrupted pulmonary vascular continuity through a paracrine mechanism, leading to massive pulmonary hemorrhage and lethality at mid-gestation when the pulmonary circulation should have started.ConclusionsOur study suggests that Apc in lung mesenchyme plays central roles in coordinating the proper development of several quite different cellular compartments including lung epithelial branching and pulmonary vascular circulation during lung organogenesis

    Bis[bis­(2-ethyl-5-methyl-1H-imidazol-4-yl-κN 3)methane](nitrato-κ2 O,O′)nickel(II) nitrate

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    In the title compound, [Ni(NO3)(C13H20N4)2]NO3, the NiII ion shows a distorted octa­hedral geometry formed by four N atoms from two bis­(2-ethyl-5-methyl-1H-imidazol-4-yl)methane ligands and two O atoms from a chelating nitrate anion. Three ethyl groups in the complex cation and the O atoms of the uncoordinated nitrate anion are disordered over two sets of positions [occupancy ratios of 0.52 (3):0.48 (3) and 0.63 (3):0.37 (3), respectively]. In the crystal, inter­molecular N—H⋯O hydrogen bonds connect the complex cations into a zigzag chain along [010] and further N—H⋯O hydrogen bonds between the chains and the uncoordinated nitrate anions lead to layers parallel to (100)

    Aqua­[bis­(2-ethyl-5-methyl-1H-imidazol-4-yl-κN 3)methane]­oxalatocopper(II) dihydrate

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    In the title compound, [Cu(C2O4)(C13H20N4)(H2O)]·2H2O, the CuII atom exhibits a distorted square-pyramidal geometry with the two N atoms of the imidazole ligand and the two O atoms of the oxalate ligand forming the basal plane, while the O atom of the coordinated water mol­ecule is in an apical position. The CuII atom is shifted 0.232 (2) Å out of the basal plane toward the water mol­ecule. The asymmetric unit is completed by two solvent water mol­ecules. These water mol­ecules participate in the formation of an intricate three-dimensionnal network of hydrogen bonds involving the coordinated water mol­ecule and the NH groups

    Small-scale fluctuation and scaling law of mixing in three-dimensional rotating turbulent Rayleigh-Taylor instability

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    The effect of rotation on small-scale characteristics and scaling law in the mixing zone of the three-dimensional turbulent Rayleigh-Taylor instability (RTI) is investigated by the lattice Boltzmann method at small Atwood number. The mixing zone width h ( t ) , the root mean square of small scale fluctuation, the spectra, and the structure functions are obtained to analyze the rotating effect. We mainly focus on the process of the development of plumes and discuss the physical mechanism in the mixing zone in rotating and nonrotating systems. The variation of kinetic energy spectra E u and temperature energy spectra E θ with the dimensionless rotation Ω τ demonstrate the suppression effect of rotation. Two scaling laws between the mixing layer width h ( t ) and dimensionless time t / τ are obtained at various Coriolis forces( √ h ( t ) ≃ t 0.9 and √ h ( t ) ≃ t 0.35 ). The rotation increasingly suppresses the growth of the mixing layer width h ( t ) . The velocity and temperature fluctuations are also suppressed by the rotation effect. The relation between the Nusselt number (Nu) and the Rayleigh number (Ra) indicates that the heat transfer is suppressed by the rotation effect in the rotating RT system. The width of the inertial subrange increasingly narrows with increasing Ω τ

    Gap Anisotropy in Iron-Based Superconductors: A Point-Contact Andreev Reflection Study of BaFe2x_{2-x}Nix_{x}As2_2 Single Crystals

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    We report a systematic investigation on c-axis point-contact Andreev reflection (PCAR) in BaFe2x_{2-x}Nix_xAs2_2 superconducting single crystals from underdoped to overdoped regions (0.075 x0.15\leq x\leq 0.15). At optimal doping (x=0.1x=0.1) the PCAR spectrum feature the structures of two superconducting gap and electron-boson coupling mode. In the s±s\pm scenario, quantitative analysis using a generalized Blonder-Tinkham-Klapwijk (BTK) formalism with two gaps: one isotropic and another angle dependent, suggest a nodeless state in strong-coupling limit with gap minima on the Fermi surfaces. Upon crossing above the optimal doping (x>0.1x > 0.1), the PCAR spectrum show an in-gap sharp narrow peak at low bias, in contrast to the case of underdoped samples (x<0.1x < 0.1), signaling the onset of deepened gap minima or nodes in the superconducting gap. This result provides evidence of the modulation of the gap amplitude with doping concentration, consistent with the calculations for the orbital dependent pair interaction mediated by the antiferromagnetic spin fluctuations.Comment: 5 pages, 4 figure

    Output Remapping Technique for Soft-Error Rate Reduction in Critical Paths

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    It is expected that the soft error rate (SER) of combinational logic will increase significantly. Previous solutions to mitigate soft errors in combinational logic suffer from delay penalty or area/power overhead. In this paper, we proposed an output remapping technique to reduce SER of critical paths. Experimental results show up to about 20X increase in Qcritical. So the SER is reduced significantly. This method does not introduce any delay penalty. The area/power overhead is limited as well. The output remapping method is based on our novel glitch width model. The analysis shows that output remapping technique works well along with technology scaling
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