Risk factors for surgical site infection after colorectal resection: a prospective single centre study. An analysis on 287 consecutive elective and urgent procedures within an institutional quality improvement project.

Aim: To determine the incidence and to investigate risk factors for surgical site infections (SSIs) in a cohort of patients undergoing colorectal surgery.

Material & Methods: Data from all consecutive patients operated at our department in an elective or in an urgent setting over a 4-month period were prospectively collected and analysed. The updated Centres for Disease Control and Prevention guidelines were used to define and to score SSIs during weekly meetings.

Beyond the compact magnetic domain wall.

Domain wall dynamics in wide submicrometer wires is investigated to understand the fundamental mechanisms that limit wall mobility, both experimentally by magneto-optical Kerr effect and by micromagnetic simulations. It is found that the dynamic domain wall structure departs significantly from the current description of a compact entity when evolving along the wire. The wall is composed of several substructures, each one propagating and evolving in a different dynamic regime with very different velocities.

Dependence of domain-wall depinning threshold current on pinning profile.

We have investigated the threshold current density required for depinning a domain wall from constrictions in NiFe nanowires, which give rise to pinning potentials of fixed amplitude but variable profile. We observed it to vary linearly with the angle of the triangular constriction. These results are reproduced using micromagnetic simulations including the adiabatic and nonadiabatic spin-torque terms.

Control of domain wall polarity by current pulses.

Direct observation of current-induced propagation of purely transverse magnetic domain walls with spin-polarized scanning electron microscopy is reported in Fe30Ni70 nanowires. After propagation, the domain walls keep their transverse nature but switch polarity in some cases. For uniform Ni70Fe30 wires, the effect is random and illustrates domain-wall propagation above the Walker threshold.