974 research outputs found

    Bis[1-(4-cyano­benz­yl)pyrazinium] bis­(1,2-dicyano­ethene-1,2-dithiol­ato)nickelate(II)

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    The asymmetric unit of the title complex, (C12H10N3)2[Ni(C4N2S2)2], consists of one 1-(4-cyano­benz­yl)pyrazinium cation and one half of an [Ni(mnt)2]2− dianion (mnt2− is 1,2-dicyano­ethene-1,2-dithiol­ate). The Ni2+ ion is located on an inversion center and is coordinated by four S atoms from two mnt2− ligands, exhibiting a square-planar coordination geometry. The cation adopts a conformation where both the pyrazine ring and the benzene ring are twisted with respect to the C—C—N reference plane by 16.5 (2) and 69.8 (1)°, respectively

    Nonlinear Ramsey interferometry with the Rosen-Zener pulses on a two-component Bose-Einstein condensate

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    We propose a feasible scheme to realize nonlinear Ramsey interferometry with a two-component Bose-Einstein condensate, where the nonlinearity arises from the interaction between coherent atoms. In our scheme, two Rosen-Zener pulses are separated by an intermediate holding period of variable duration and through varying the holding period we have observed nice Ramsey interference patterns in time domain. In contrast to the standard Ramsey fringes our nonlinear Ramsey patterns display diversiform structures ascribed to the interplay of the nonlinearity and asymmetry. In particular, we find that the frequency of the nonlinear Ramsey fringes exactly reflects the strength of nonlinearity as well as the asymmetry of system. Our finding suggests a potential application of the nonlinear Ramsey interferometry in calibrating the atomic parameters such as scattering length and energy spectrum.Comment: 8 pages, 9 figure

    Kaj država pričakuje od državnega programa obvadovanja raka

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    Locked-to-sliding phase transition has been studied in the driven two-dimensional Frenkel-Kontorova model with the square symmetric substrate potential. It is found that as the driving force increases, the system transfers from the locked state to the sliding state where the motion of particles is in the direction different from that of driving force. With the further increase in driving force, at some critical value, the particles start to move in the direction of driving force. These two critical forces, the static friction or depinning force, and the kinetic friction force for which particles move in the direction of driving force have been analyzed for different system parameters. Different scenarios of phase transitions have been examined and dynamical phases are classified. In the case of zero misfit angle, the analytical expressions for static and kinetic friction force have been obtained

    The Hidden Nematic Fluctuations in the Triclinic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 Superconductor Revealed by Ultrafast Optical Spectroscopy

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    We reported the quasiparticle relaxation dynamics of an optimally doped triclinic iron-based superconductor (Ca0.85_{0.85}La0.15_{0.15})10_{10}(Pt3_3As8_8)(Fe2_2As2_2)5_5 with bulk TcT_c = 30 K using polarized ultrafast optical pump-probe spectroscopy. Our results reveal anisotropic transient reflectivity induced by nematic fluctuations develops below TnemT_{nem} \approx 120 K and persists in the superconducting states. Measurements under high pump fluence reveal three distinct, coherent phonon modes at frequencies of 1.6, 3.5, and 4.7 THz, corresponding to A1g(1)A_{1g}(1), EgE_g, and A1g(2)A_{1g}(2) modes, respectively. The high-frequency A1g(2)A_{1g}(2) mode corresponds to the cc-axis polarized vibrations of FeAs planes with a nominal electron-phonon coupling constant λA1g(2)\lambda _{A_{1g}(2)} \approx 0.139 ±\pm 0.02. Our findings suggest that the superconductivity and nematic state are compatible but competitive at low temperatures, and the A1gA_{1g} phonons play an important role in the formation of Cooper pairs in (Ca0.85_{0.85}La0.15_{0.15})10_{10}(Pt3_3As8_8)(Fe2_2As2_2)5_5.Comment: 6 pages, 3 figures and Supplemental Material

    Structure–Activity Relationship of Halophenols as a New Class of Protein Tyrosine Kinase Inhibitors

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    A series of new benzophenone and diphenylmethane halophenol derivatives were prepared. Their structures were established based on 1H NMR, 13C NMR and HRMS data. All prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) inhibitory activities. The effects of modification of the linker, functional groups and substituted positions at the phenyl ring on PTK inhibitory activity were investigated. Twelve halophenols showed significant PTK inhibitory activity. Among them, compounds 6c, 6d, 7d, 9d, 10d, 11d and 13d exhibited stronger activities than that of genistein, the positive reference compound. The results gave a relatively full and definite description of the structure–activity relationship and provided a foundation for further design and structure optimization of the halophenols

    The hornwort genome and early land plant evolution

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    Hornworts, liverworts and mosses are three early diverging clades of land plants, and together comprise the bryophytes. Here, we report the draft genome sequence of the hornwort Anthoceros angustus. Phylogenomic inferences confirm the monophyly of bryophytes, with hornworts sister to liverworts and mosses. The simple morphology of hornworts correlates with low genetic redundancy in plant body plan, while the basic transcriptional regulation toolkit for plant development has already been established in this early land plant lineage. Although the Anthoceros genome is small and characterized by minimal redundancy, expansions are observed in gene families related to RNA editing, UV protection and desiccation tolerance. The genome of A. angustus bears the signatures of horizontally transferred genes from bacteria and fungi, in particular of genes operating in stress-response and metabolic pathways. Our study provides insight into the unique features of hornworts and their molecular adaptations to live on land
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