59 research outputs found

    Observation of Magnetic Flux Generated Spontaneously During a Rapid Quench of Superconducting Films

    Full text link
    We report observations of spontaneous formation of magnetic flux lines during a rapid quench of YBa2_{2}Cu3_{3}O7δ_{7-\delta} films through Tc_{c}. This effect is predicted according to the Kibble-Zurek mechanism of creation of topological defects of the order parameter during a symmetry-breaking phase transition. Our previous experiment, at a quench rate of 20K/sec, gave null results. In the present experiment, the quench rate was increased to \TEXTsymbol{>} 108^{8} K/sec. Within experimental resolution, the dependence of the measured flux on the cooling rate is consistent with the prediction

    Genetic interaction mapping informs integrative structure determination of protein complexes

    Get PDF
    Determining structures of protein complexes is crucial for understanding cellular functions. Here, we describe an integrative structure determination approach that relies on in vivo measurements of genetic interactions. We construct phenotypic profiles for point mutations crossed against gene deletions or exposed to environmental perturbations, followed by converting similarities between two profiles into an upper bound on the distance between the mutated residues. We determine the structure of the yeast histone H3-H4 complex based on similar to 500,000 genetic interactions of 350 mutants. We then apply the method to subunits Rpb1-Rpb2 of yeast RNA polymerase II and subunits RpoB-RpoC of bacterial RNA polymerase. The accuracy is comparable to that based on chemical cross-links; using restraints from both genetic interactions and cross-links further improves model accuracy and precision. The approach provides an efficient means to augment integrative structure determination with in vivo observations
    corecore