1,008 research outputs found

    Magnetic dipole induced guided vortex motion

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    We present evidence of magnetically controlled guided vortex motion in a hybrid superconductor/ferromagnet nanosystem consisting of an Al film on top of a square array of permalloy square rings. When the rings are magnetized with an in-plane external field H, an array of point-like dipoles with moments antiparallel to H, is formed. The resulting magnetic template generates a strongly anisotropic pinning potential landscape for vortices in the superconducting layer. Transport measurements show that this anisotropy is able to confine the flux motion along the high symmetry axes of the square lattice of dipoles. This guided vortex motion can be either re-routed by 90 degrees by simply changing the dipole orientation or even strongly suppressed by inducing a flux-closure magnetic state with very low stray fields in the rings.Comment: 5 pages, 3 figure

    Conversion of bright magneto-optical resonances into dark at fixed laser frequency for D2 excitation of atomic rubidium

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    Nonlinear magneto-optical resonances on the hyperfine transitions belonging to the D2 line of rubidium were changed from bright to dark resonances by changing the laser power density of the single exciting laser field or by changing the vapor temperature in the cell. In one set of experiments atoms were excited by linearly polarized light from an extended cavity diode laser with polarization vector perpendicular to the light's propagation direction and magnetic field, and laser induced fluorescence (LIF) was observed along the direction of the magnetic field, which was scanned. A low-contrast bright resonance was observed at low laser power densities when the laser was tuned to the Fg=2 --> Fe=3 transition of Rb-87 and near to the Fg=3 --> Fe=4 transition of Rb-85. The bright resonance became dark as the laser power density was increased above 0.6mW/cm2 or 0.8 mW/cm2, respectively. When the Fg=2 --> Fe=3 transition of Rb-87 was excited with circularly polarized light in a second set of experiments, a bright resonance was observed, which became dark when the temperature was increased to around 50C. The experimental observations at room temperature could be reproduced with good agreement by calculations based on a theoretical model, although the theoretical model was not able to describe measurements at elevated temperatures, where reabsorption was thought to play a decisive role. The model was derived from the optical Bloch equations and included all nearby hyperfine components, averaging over the Doppler profile, mixing of magnetic sublevels in the external magnetic field, and a treatment of the coherence properties of the exciting radiation field.Comment: 9 pages, 7 figure

    Health-Related Quality of Life after Hysterectomy for Endometrial Cancer: The Impact of Enhanced Recovery after Surgery Shifting Paradigm

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    Objectives: Enhanced recovery after surgery (ERAS) protocols provide well-known benefits in the immediate recovery with a shorter length of stay (LOS) also in gynecological surgery. However, the impact of ERAS has not been clearly showed yet regarding long-term consequences and health-related quality of life (HRQL). The aim of this study is to investigate the impact of ERAS on HRQL after hysterectomy for endometrial cancer. Design: Observational retrospective study with propensity score matching (PSM). Participants We administered the SF-36 validated questionnaire to women underwent hysterectomy and lymph nodal staging before and after introducing ERAS protocol, getting, respectively, a standard practice (SP) and ERAS group Settings Academic hospital Methods We collected demographic, clinical, surgical and postoperative data and performed a PSM of the baseline coufouders. We administered the questionnaire four weeks after the surgery. The SF-36 measures HRQL using eight scales: physical functioning (PF), role physical (RLP), bodily pain (BP), general health (GH), vitality (Vt), social functioning (SF), role emotional (RLE) and mental health (MH). Results After PSM, we enrolled a total of 154 patients, 77 in each group (SP and ERA). The two groups were similar in terms of age, BMI, anaesthesiologic risk, Charlson comorbidity index (CCI) and surgical technique (minimally invasive versus open access). Median LOS was shorter for ERAS group (5 versus 3 days; p = 0.02), while no significant differences were registered in the rates of postoperative complications (16.9% versus 17.4%; p = 0.66). Response rates to SF-36 questionnaire were 89% and 92%, respectively, in SP and ERAS group. At multivariate analyzes, the mean scores of SF-36 questionnaire, registered at 28 days weeks after surgery (range 26-32 days), were significantly higher in ERAS group for PF (73.3 vs 91.6; p < 0.00), RLP (median 58.3 vs 81.2; p = 0.02) and SF (37.5 versus 58.3; p = 0.01) domains, when compared to SP patients. Limitations Further follow-up was not possible due to the anonymized data derived from clinical audit. Conclusions ERAS significantly increases HRQL of women underwent surgery for endometrial cancer. HRQL assessment should be routinary implemented in the ERAS protocol

    Optical response of a misaligned and suspended Fabry-Perot cavity

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    The response to a probe laser beam of a suspended, misaligned and detuned optical cavity is examined. A five degree of freedom model of the fluctuations of the longitudinal and transverse mirror coordinates is presented. Classical and quantum mechanical effects of radiation pressure are studied with the help of the optical stiffness coefficients and the signals provided by an FM sideband technique and a quadrant detector, for generic values of the product Ï–Ï„\varpi \tau of the fluctuation frequency times the cavity round trip. A simplified version is presented for the case of small misalignments. Mechanical stability, mirror position entanglement and ponderomotive squeezing are accommodated in this model. Numerical plots refer to cavities under test at the so-called Pisa LF facility.Comment: 14 pages (4 figures) submitted to Phys. Rev.

    Transformation of electromagnetically induced transparency into absorption in a thermal potassium optical cell with spin preserving coating

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    We report a new experimental approach where an order of magnitude enhancement of the electromagnetically induced absorption (EIA) resonance contrast, thus making it similar to that of the EIT resonance contrast is observed under the same conditions. The EIA signal results from the interaction of a weak probe beam with a ground state that has been driven by the pump (counter-propagating) beam. Probe absorption spectra are presented where the laser frequency is slowly detuned over the D 1 line of 39 K vapor contained in a cell with a PDMS antirelaxation coating. In addition to the frequency detuning, a magnetic field orthogonal to the laser beams is scanned around zero value at a higher rate. With both laser beams linearly polarized, an EIT resonance is observed. However, changing the pump beam polarization from linear to circular reverses the resonance signal from EIT to EIA

    Adjuvant Radiotherapy for Groin Node Metastases Following Surgery for Vulvar Cancer: A Systematic Review

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    Background: Lymph node metastasis in vulvar cancer is a critical prognostic factor associated with higher recurrence and decreased survival. A survival benefit is reported with adjuvant radiotherapy but with potential significant morbidity. We aim to clarify whether there is high-quality evidence to support the use of adjuvant radiotherapy in this setting. Objectives: The aim of the study was to assess the effectiveness and safety of adjuvant radiotherapy to locoregional metastatic nodal areas. Search Methods: We conducted a comprehensive and systematic literature search of MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Google Scholar, ClinicalTrials.gov, and the National Cancer Institute. We considered only randomized controlled trials (RCTs). Main Results: We identified 1,760 records and finally retrieved only one eligible RCT (114 participants with positive inguinofemoral lymph nodes). All women had undergone radical vulvectomy and bilateral inguinal lymphadenectomy and had been randomized to adjuvant radiotherapy or to intraoperative ipsilateral pelvic lymphadenectomy without adjuvant radiotherapy. At 6 years, the overall survival (OS) was 51% versus 41% in favor of radiotherapy (HR 0.61; 95% CI 0.30–1.3) without significance and with very low certainty of evidence. At 6 year, the cumulative incidence of cancer-related deaths was 29% versus 51% in favor of adjuvant radiotherapy (HR 0.49; 95% CI 0.28–0.87). Recurrence-free survival at 6 years was 59% after adjuvant radiotherapy versus 48% after pelvic lymphadenectomy (HR 0.39; 95% CI 0.17–0.88). Three (5.3%) versus 13 (24.1%) groin recurrences were noted, respectively, in the adjuvant radiotherapy and pelvic lymphadenectomy groups. There was no significant difference in acute toxicities for pelvic lymphadenectomy compared to radiotherapy. In women with positive pelvic lymph nodes (20%), the OS at 6 year was 36% compared with 13% in favor of adjuvant radiotherapy. Late cutaneous toxicity rate appeared to be greater after radiotherapy (19% vs. 15%) but with less chronic lymphedema (16% vs. 22%). Conclusion: There is only very low-quality evidence on administering adjuvant radiotherapy for inguinal lymph node metastases. Although the identified study was a multicenter RCT, there was a reasonable imprecision and inconsistency because of small study numbers, wide confidence intervals in the data, and early trial closure, resulting in downgrading of the evidence
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