44,177 research outputs found
A subdiffusive Navier-Stokes-Voigt system
No full textFor ν∈(0,1), we analyze the system of equations on the two dimensional domain Ω in the unknown function u=(u1(x,t),u2(x,t))ut−μΔu−γΔ∂t νu+u⋅∇u=−∇p+f,divu=0, where ∂t ν denotes the Riemann–Liouville fractional derivative of order ν. Under suitable conditions on the given data, the global existence and uniqueness of strong solutions to the related initial–boundary value problems are established for ν∈(0,1/2). The convergence of the strong solution to the one of the corresponding initial–boundary value problem to the Navier–Stokes equations is discussed, in the limit ν→0. We also present several numerical tests illustrating this convergence
4D Flow MRI hemodynamic benchmarking of surgical bioprosthetic valves
Get PDFPurpose: We exploited 4-dimensional flow magnetic resonance imaging (4D Flow), combined with a standardized in vitro setting, to establish a comprehensive benchmark for the systematic hemodynamic comparison of surgical aortic bioprosthetic valves (BPVs). Materials and methods: 4D Flow analysis was performed on two small sizes of three commercialized pericardial BPVs (TrifectaTM GT, Carpentier-Edwards PERIMOUNT Magna and Crown PRT®). Each BPV was tested over a clinically pertinent range of continuous flow rates within an in vitro MRI-compatible system, equipped with pressure transducers. In-house 4D Flow post-processing of the post-valvular velocity field included the quantification of BPV effective orifice area (EOA), transvalvular pressure gradients (TPG), kinetic energy and viscous energy dissipation. Results: The 4D Flow technique effectively captured the 3-dimensional flow pattern of each device. Trifecta exhibited the lowest range of velocity and kinetic energy, maximized EOA (p < 0.0001) and minimized TPGs (p ≤ 0.015) if compared with Magna and Crown, these reporting minor EOA difference s (p ≥ 0.042) and similar TPGs (p ≥ 0.25). 4D Flow TPGs estimations strongly correlated against ground-truth data from pressure transducers; viscous energy dissipation proved to be inversely proportional to the fluid jet penetration. Conclusion: The proposed 4D Flow analysis pinpointed consistent hemodynamic differences among BPVs, highlighting the not negligible effect of device size on the fluidynamic outcomes. The efficacy of non-invasive 4D Flow MRI protocol could shed light on how standardize the comparison among devices in relation to their actual hemodynamic performances and improve current criteria for their selection
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
Get PDFFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
APC/C and SCFcyclin F Constitute a Reciprocal Feedback Circuit Controlling S-Phase Entry
Get PDFSummaryThe anaphase promoting complex/cyclosome (APC/C) is an ubiquitin ligase and core component of the cell-cycle oscillator. During G1 phase, APC/C binds to its substrate receptor Cdh1 and APC/CCdh1 plays an important role in restricting S-phase entry and maintaining genome integrity. We describe a reciprocal feedback circuit between APC/C and a second ubiquitin ligase, the SCF (Skp1-Cul1-F box). We show that cyclin F, a cell-cycle-regulated substrate receptor (F-box protein) for the SCF, is targeted for degradation by APC/C. Furthermore, we establish that Cdh1 is itself a substrate of SCFcyclin F. Cyclin F loss impairs Cdh1 degradation and delays S-phase entry, and this delay is reversed by simultaneous removal of Cdh1. These data indicate that the coordinated, temporal ordering of cyclin F and Cdh1 degradation, organized in a double-negative feedback loop, represents a fundamental aspect of cell-cycle control. This mutual antagonism could be a feature of other oscillating systems
Data set from Sturla F, Piatti F, Jaworek M, Lucherini F, Pluchinotta FR, Siryk SV, Giese D, Vismara R, Tasca G, Menicanti L, Redaelli A, Lombardi M. 4D Flow MRI hemodynamic benchmarking of surgical bioprosthetic valves. Magn Reson Imaging. 2020 May;68:18-29. doi: 10.1016/j.mri.2020.01.006. Epub 2020 Jan 22. PMID: 31981709.
No full textData set from the article Sturla F, Piatti F, Jaworek M, Lucherini F, Pluchinotta FR, Siryk SV, Giese D, Vismara R, Tasca G, Menicanti L, Redaelli A, Lombardi M. 4D Flow MRI hemodynamic benchmarking of surgical bioprosthetic valves. Magn Reson Imaging. 2020 May;68:18-29. doi: 10.1016/j.mri.2020.01.006. Epub 2020 Jan 22. PMID: 31981709.
Abstract
Purpose: We exploited 4-dimensional flow magnetic resonance imaging (4D Flow), combined with a standardized in vitro setting, to establish a comprehensive benchmark for the systematic hemodynamic comparison of surgical aortic bioprosthetic valves (BPVs).
Materials and methods: 4D Flow analysis was performed on two small sizes of three commercialized pericardial BPVs (Trifecta™ GT, Carpentier-Edwards PERIMOUNT Magna and Crown PRT®). Each BPV was tested over a clinically pertinent range of continuous flow rates within an in vitro MRI-compatible system, equipped with pressure transducers. In-house 4D Flow post-processing of the post-valvular velocity field included the quantification of BPV effective orifice area (EOA), transvalvular pressure gradients (TPG), kinetic energy and viscous energy dissipation.
Results: The 4D Flow technique effectively captured the 3-dimensional flow pattern of each device. Trifecta exhibited the lowest range of velocity and kinetic energy, maximized EOA (p < 0.0001) and minimized TPGs (p ≤ 0.015) if compared with Magna and Crown, these reporting minor EOA difference s (p ≥ 0.042) and similar TPGs (p ≥ 0.25). 4D Flow TPGs estimations strongly correlated against ground-truth data from pressure transducers; viscous energy dissipation proved to be inversely proportional to the fluid jet penetration.
Conclusion: The proposed 4D Flow analysis pinpointed consistent hemodynamic differences among BPVs, highlighting the not negligible effect of device size on the fluidynamic outcomes. The efficacy of non-invasive 4D Flow MRI protocol could shed light on how standardize the comparison among devices in relation to their actual hemodynamic performances and improve current criteria for their selection
Noise of open and semi-closed bileaflet prosthetic mitral valve
No full textIn this paper, in vitro experimental research results of the hydrodynamic noise of open and semi-closed bileaflet prosthetic mitral valve are presented. The bileaflet valve Sorin biomedica cardio was used in this research. Group of pressure fluctuation sensors and sensors of absolute pressure registered noise of the vortex structures and the jet flow. For the open bileaflet valve, the mean pressures are higher near the side jet than near the central jet. The lowest mean pressures occur near the side jet downstream to the semi-closed valve. Spectral levels of the pressure fluctuations significantly varied for different flow rate in the frequency range from 0.03 Hz to 200 Hz. For the semi-closed valve near the side jet, the power spectral densities of the pressure fluctuations are (3. . . 4) times greater than for the open one. It was found that hydroacoustic measurements could be an effective basis for developing diagnostic equipment in order to check the use of the bileaflet prosthetic mitral valve
Corrigendum to “Presence and function of kisspeptin/KISS1R system in swine ovarian follicles” (Theriogenology (2018) 115 (1–8), (S0093691X1830147X), (10.1016/j.theriogenology.2018.04.006))
No full textThe authors regret the following changes to the author group G. Basinia, F. Grassellia, S. Bussolatia, R. Ciccimarraa, M. Maranesib, A. Bufalarib, C. Dall'Agliob, F. Parilloc,#, M. Zeranib,c,*. a Dipartimento di Scienze Mediche Veterinarie, Università di Parma, 43126 Parma, Italy. b Dipartimento di Medicina Veterinaria, Università di Perugia, 06126 Perugia Italy. c Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, 62024 Matelica Italy. # Deceased. * Corresponding author: tel.: +39 0755857642; fax +39 0755857654. E-mail address: [email protected] (M. Zerani). And to the acknowledgements and figures
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Get PDFMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Lympha technique for primary and early secondary prevention of lymphedema following cancer treatment
No full textLYMPHA proved to be an effective preventive procedure that contributes in giving our oncological patients a good quality of life. In this presentation, the author will report indications, technical aspects and benefits of LYMPHA technique
New formulae for Zagreb indices
No full textInternational Conference on Numerical Analysis and Applied Mathematics (ICNAAM) -- SEP 19-25, 2016 -- Rhodes, GREECEIn this paper, we study with some graph descriptors also called topological indices. These descriptors are useful in determination of some properties of chemical structures and preferred to some earlier descriptors as they are more practical. Especially the first and second Zagreb indices together with the first and second multiplicative Zagreb indices are considered and they are calculated in terms of the smallest and largest vertex degrees and vertex number for some well-known classes of graphs.Uludag UniversityUludag University [F-2015/17, F-2015/23]; Selcuk UniversitySelcuk UniversityThe first author was supported by the Research Fund of Uludag University project no: F-2015/17, F-2015/23. The last author is supported by Selcuk University Research Fund
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