| 1. |
- Akhmedov, Evgeny, et al.
(författare)
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Interplay of type I and type II seesaw contributions to neutrino mass
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :1, s. 043-
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Tidskriftsartikel (refereegranskat)abstract
- Type I and type II seesaw contributions to the mass matrix of light neutrinos are inherently related if left-right symmetry is realized at high energy scales. We investigate implications of such a relation for the interpretation of neutrino data. We proved recently that the left-right symmetric seesaw equation has eight solutions, related by a duality property, for the mass matrix of right-handed neutrinos M-R. In this paper the eight allowed structures of M-R are reconstructed analytically and analyzed numerically in a bottom-up approach. We study the dependence of right-handed neutrino masses on the mass spectrum of light neutrinos, mixing angle theta(13), leptonic CP violation, scale of left-right symmetry breaking and on the hierarchy in neutrino Yukawa couplings. The structure of the seesaw formula in several specific SO(10) models is explored in the light of the duality. The outcome of leptogenesis may depend crucially on the choice among the allowed structures of M-R and on the level crossing between right-handed neutrino masses.
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| 2. |
- Ammirati, Enrico, et al.
(författare)
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Outcome of patients on heart transplant list treated with a continuous-flow left ventricular assist device : Insights from the TRans-Atlantic registry on VAd and TrAnsplant (TRAViATA)
- 2021
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273. ; 324
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Tidskriftsartikel (refereegranskat)abstract
- Background: Geographic variations in management and outcomes of individuals supported by continuous-flow left ventricular assist devices (CF-LVAD) between the United States (US) and Europe (EU) is largely unknown. Methods: We created a retrospective, multinational registry of 524 patients who received a CF-LVAD (either HVAD or Heartmate II) between January 2008 and April 2017. Follow up spanned from date of CF-LVAD implant to post-HTx period with a median follow up of 44.8 months. Results: The cohort included 299 (57.1%) EU and 225 (42.9%) US patients. Although the US cohort was significantly older with a higher prevalence of comorbidities, survival was similar between the cohorts (US 63.1%, EU 68.4% at 5 years, unadjusted log-rank test p = 0.43).Multivariate analyses suggested that older age, higher body mass index, elevated creatinine, use of temporary mechanical circulatory support prior CF-LVAD, and implantation of HVAD were associated with increased mortality. Among CF-LVAD patients undergoing HTx, the median time on CF-LVAD support was shorter in the US, meanwhile US donors were younger. Finally, the pattern of adverse events (stroke, gastrointestinal bleedings, late right ventricular failure, and driveline infection) during support differed significantly between US and EU. Conclusions: Although waitlisted patients in the US on CF-LVAD have higher risk comorbid conditions, the overall outcome is similar in US and EU. Geographic variations with regards to donor characteristics, duration of CF-LVAD support prior to transplant, and adverse events on support can explain the disparity in the utilization of mechanical bridge to transplant strategy between US and EU.
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| 3. |
- Frigerio, Jacopo, et al.
(författare)
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Mid-infrared second harmonic generation in Ge/SiGe coupled quantum wells
- 2020
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Ingår i: 2020 IEEE Photonics Conference, IPC 2020 - Proceedings. ; September 2020
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Konferensbidrag (refereegranskat)abstract
- We present the theoretical investigation and the experimental demonstration of second harmonic generation in the mid-infrared by hole-doped Ge/SiGe asymmetric quantum wells.
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| 4. |
- Frigerio, Jacopo, et al.
(författare)
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Mid-infrared second harmonic generation with Ge quantum wells
- 2021
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Ingår i: IEEE International Conference on Group IV Photonics GFP. - 1949-2081. ; 2021-December
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Konferensbidrag (refereegranskat)abstract
- We present the experimental demonstration of second harmonic generation in the mid-infrared by hole-doped Ge/SiGe asymmetric quantum wells.
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| 5. |
- Frigerio, Jacopo, et al.
(författare)
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Second Harmonic Generation in Germanium Quantum Wells for Nonlinear Silicon Photonics
- 2021
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 8:12, s. 3573-3582
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Tidskriftsartikel (refereegranskat)abstract
- Second-harmonic generation (SHG) is a direct measure of the strength of second-order nonlinear optical effects, which also include frequency mixing and parametric oscillations. Natural and artificial materials with broken center-of-inversion symmetry in their unit cell display high SHG efficiency, however, the silicon-foundry compatible group IV semiconductors (Si, Ge) are centrosymmetric, thereby preventing full integration of second-order nonlinearity in silicon photonics platforms. Here we demonstrate strong SHG in Ge-rich quantum wells grown on Si wafers. Unlike Si-rich epilayers, Ge-rich epilayers allow for waveguiding on a Si substrate. The symmetry breaking is artificially realized with a pair of asymmetric coupled quantum wells (ACQW), in which three of the quantum-confined states are equidistant in energy, resulting in a double resonance for SHG. Laser spectroscopy experiments demonstrate a giant second-order nonlinearity at mid-infrared pump wavelengths between 9 and 12 μm. Leveraging on the strong intersubband dipoles, the nonlinear susceptibility χ(2) almost reaches 105 pm/V, 4 orders of magnitude larger than bulk nonlinear materials for which, by the Miller's rule, the range of 10 pm/V is the norm.
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| 6. |
- Giani, Alessandro, et al.
(författare)
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Benchmarking of minimally invasive distal pancreatectomy with splenectomy: European multicentre study
- 2022
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Ingår i: British Journal of Surgery. - : OXFORD UNIV PRESS. - 0007-1323 .- 1365-2168. ; 109:11, s. 1124-1130
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to assess best achievable outcomes in minimally invasive distal pancreatectomy with splenectomy, applying the Achievable Benchmark of Care method. This method of assessing outcomes should positively encourage comparisons, allowing single surgeons or entire units to anonymously and individually recognize what works well and where there might be room for improvement. Background Benchmarking is the process to used assess the best achievable results and compare outcomes with that standard. This study aimed to assess best achievable outcomes in minimally invasive distal pancreatectomy with splenectomy (MIDPS). Methods This retrospective study included consecutive patients undergoing MIDPS for any indication, between 2003 and 2019, in 31 European centres. Benchmarks of the main clinical outcomes were calculated according to the Achievable Benchmark of Care (ABC (TM)) method. After identifying independent risk factors for severe morbidity and conversion, risk-adjusted ABCs were calculated for each subgroup of patients at risk. Results A total of 1595 patients were included. The ABC was 2.5 per cent for conversion and 8.4 per cent for severe morbidity. ABC values were 160 min for duration of operation time, 8.3 per cent for POPF, 1.8 per cent for reoperation, and 0 per cent for mortality. Multivariable analysis showed that conversion was associated with male sex (OR 1.48), BMI exceeding 30 kg/m(2) (OR 2.42), multivisceral resection (OR 3.04), and laparoscopy (OR 2.24). Increased risk of severe morbidity was associated with ASA fitness grade above II (OR 1.60), multivisceral resection (OR 1.88), and robotic approach (OR 1.87). Conclusion The benchmark values obtained using the ABC method represent optimal outcomes from best achievable care, including low complication rates and zero mortality. These benchmarks should be used to set standards to improve patient outcomes.
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