Dynamics of paramagnetic permanent chains and self-assembled clusters under a rapidly rotating magnetic field.

We study experimentally and theoretically the dynamics of permanent paramagnetic chains and mixed clusters formed by permanent paramagnetic chains and paramagnetic particles under the influence of a time-varying magnetic field. First, we examine the dynamics of permanent chains at high frequencies (∼50 to 1000 Hz). These permanent chains exhibit continuous rotational motion with a frequency several orders of magnitude lower than that of the magnetic field.

Immediate postpartum assessment of the anal sphincter by endovaginal ultrasound: An experimental study.

Introduction And Hypothesis: Obstetric anal sphincter injuries are frequently missed and carry a significant risk for the development of anal incontinence. Immediate postpartum endoanal ultrasound increases identification of these injuries but is rarely employed. We hypothesize that endovaginal ultrasound could be a feasible and easily available alternative sonographic tool to improve early diagnosis of anal sphincter tears.

Rotation dynamics and internal structure of self-assembled binary paramagnetic colloidal clusters.

We study experimentally and theoretically the dynamics of two-dimensional self-assembled binary clusters of paramagnetic colloids of two different sizes and magnetic susceptibilities under a time-varying magnetic field. Due to the continuous energy input by the rotating field, these clusters are at a state of dissipative nonequilibrium. Dissipative viscoelastic shear waves traveling around their interface enable the rotation of isotropic binary clusters.

Immediate postpartum assessment of the anal sphincter by endovaginal ultrasound: a new technical approach.

Introduction And Hypothesis: In this study we described a new technical approach to adapt endovaginal ultrasound scanning of the anal sphincter complex to the immediate postpartum period.

Methods: We analyzed the clinical and ultrasonographic examinations of 18 primiparous women presenting deep perineal tears with potential or clearly identified lesions of the anal sphincter. Potential anal sphincter lesion was defined as a second degree perineal tear extending close to the anal sphincter with exposition of its capsule or muscular fibers.

Dissipative non-equilibrium dynamics of self-assembled paramagnetic colloidal clusters.

We study experimentally and theoretically the dynamics of two-dimensional clusters of paramagnetic colloids under a time-varying magnetic field. These self-assembled clusters are a dissipative non-equilibrium system with shared features with aggregates of living matter. We investigate the dynamics of cluster rotation and develop a theoretical model to explain the emergence of collective viscoelastic properties.