140 research outputs found
Sometimes neither water nor fire are more useful than friendship — A new risk score for prediction of contrast-induced nephropathy (CIN) and long-term adverse outcomes in patients undergoing coronary angiography
Does the inflow velocity profile influence physiologically relevant flow patterns in computational hemodynamic models of left anterior descending coronary artery?
Patient-specific computational fluid dynamics is a powerful tool for investigating the hemodynamic risk in coronary arteries. Proper setting of flow boundary conditions in computational hemodynamic models of coronary arteries is one of the sources of uncertainty weakening the findings of in silico experiments, in consequence of the challenging task of obtaining in vivo 3D flow measurements within the clinical framework. Accordingly, in this study we evaluated the influence of assumptions on inflow velocity profile shape on coronary artery hemodynamics. To do that, (1) ten left anterior descending coronary artery (LAD) geometries were reconstructed from clinical angiography, and (2) eleven velocity profiles with realistic 3D features such as eccentricity and differently shaped (single- and double-vortex) secondary flows were generated analytically and imposed as inflow boundary conditions. Wall shear stress and helicity-based descriptors obtained prescribing the commonly used parabolic velocity profile were compared with those obtained with the other velocity profiles. Our findings indicated that the imposition of idealized velocity profiles as inflow boundary condition is acceptable as long the results of the proximal vessel segment are not considered, in LAD coronary arteries. As a pragmatic rule of thumb, a conservative estimation of the length of influence of the shape of the inflow velocity profile on LAD local hemodynamics can be given by the theoretical entrance length for cylindrical conduits in laminar flow conditions
Postural counseling represents a novel option in pain management of fibromyalgia patients
Background: Chronic pain is a key symptom in fibromyalgia (FM), and its management is still challenging for rheumatologists in daily practice. FM patients show psychological and psychiatric manifestations, going from mood and emotional disorders to depression and alexithymia that negatively impact their quality of life, limiting their daily activities. Since pharmacological strategies have a limited efficacy in FM pain, alternative or complementary non-pharmacological approaches have been introduced in the clinical management of FM. Patients and methods: This is a retrospective study on FM patients (n=52) treated with a novel integrated postural counseling (PC) rehabilitation program carried out by a counselor physiotherapist. The clinical impact of PC was evaluated by 1) a semi-structured interview using an ad hoc modified questionnaire McGill Illness Narrative Interview (MINI) 1 to obtain data on pain management by highlighting everyday experience of living with pain and 2) an FM impact questionnaire (FIQ) total score. Results: Two main structures of narrative emplotment of FM illness were recognized: 1) the cumulative life narrative structure (46.15%) and 2) the broken life (53.85%) narrative structure. Baseline FIQ score was 77.38±7.77, and it was significantly reduced after PC to 39.12±13.27 (P<0.0001). Although well-being still requires further definition as outcome in pain management, it is important for FM patients, dealing with pain-related sensations, thoughts and feelings and limiting their daily activities. In our study, 87.5% of interviewed FM patients reported an improvement in their well-being after PC. Conclusion: Our data suggest that an integrated PC program positively impacts chronic pain and fatigue based on self-management strategies. PC allows FM patients to resume their own life and regenerate their own image. Finally, we propose the introduction of the evaluation of the ability to resume daily activities as the target of rehabilitation programs in FM
From the quantum transfer matrix to the quench action: the Loschmidt echo in XXZ Heisenberg spin chains
We consider the computation of the Loschmidt echo after quantum quenches in the interacting XXZ Heisenberg spin chain both for real and imaginary times. We study two-site product initial states, focusing in particular on the N\ue9el and tilted N\ue9el states. We apply the Quantum Transfer Matrix (QTM) approach to derive generalized TBA equations, which follow from the fusion hierarchy of the appropriate QTM's. Our formulas are valid for arbitrary imaginary time and for real times at least up to a time t0, after which the integral equations have to be modified. In some regimes, t0 is seen to be either very large or infinite, allowing to explore in detail the post-quench dynamics of the system. As an important part of our work, we show that for the N\ue9el state our imaginary time results can be recovered by means of the quench action approach, unveiling a direct connection with the quantum transfer matrix formalism. In particular, we show that in the zero-time limit, the study of our TBA equations allows for a simple alternative derivation of the recently obtained Bethe ansatz distribution functions for the N\ue9el, tilted N\ue9el and tilted ferromagnet states
RUOLO DELLA RM-DWI INTEGRATA DAL PARAMETRO ADC NELLO STUDIO DEL COLESTEATOMA
: La Risonanza Magnetica pesata in diffusione (RM-DWI) distingue qualitativamente il colesteatoma dal tessuto di granulazione nei pazienti con otite media cronica. Il calcolo del coefficiente di diffusione apparente (ADC) consente un'analisi quantitativa identificando un cut-off numerico che differenzia le due tipologie tissutali.
MATERIALI E METODI: lo studio retrospettivo ha riguardato 100 pazienti sottoposti a Timpanoplastica per colesteatoma primario o residuo/recidivante. Tutti i pazienti sono stati sottoposti a RM-DWI preoperatoria tra Aprile 2015 e Marzo 2019, con calcolo di ADC (R-version 3.2.5). La presenza di colesteatoma è stata accertata intraoperatoriamente e confermata istologicamente.
RISULTATI: i reperti chirurgici di 100 pazienti sono stati confrontati con i valori medi ADC ed analizzata la distribuzione di quest’ultimi per colesteatoma/tessuto di granulazione, evidenziando due gruppi. La differenza nel valore medio di ADC tra colesteatoma (0,86 × 10-3mm2/s) e tessuto di granulazione (2.22×10-3mm2/s) ha rilevato una differenza statisticamente significativa di ADC per i pazienti con/senza colesteatoma (p <2.2 × 10-16). Il modello binomiale di regressione logistica prevede la probabilità dello stato patologico, mediante ADC. Il potere predittivo di questo modello è stato misurato mediante curva ROC e applicando la statistica Youden J sulla curva abbiamo stabilito un valore di probabilità di ~ 0,6 per definire un cut-off (specificità = 1.0 sensibilità = 0.9861111) pari a ADC=1,71×10-3mm2/s.
CONCLUSIONI: lo studio ha evidenziato che è possibile stabilire un cut-off di ADC per identificare pre-operatoriamente con elevata significatività statistica la presenza di matrice colesteatomatosa. In tal modo la RM-DWI diviene una “tool diagnostico” utile ed affidabile in quei casi in cui il colesteatoma non è certamente evidenziabile in otomicroscopia e/o nel follow-up di pazienti già sottoposti a primo tempo chirurgico
Accuracy of the PARIS score and PCI complexity to predict ischemic events in patients treated with very thin stents in unprotected left main or coronary bifurcations
Prediction of All-Cause Mortality Following Percutaneous Coronary Intervention in Bifurcation Lesions Using Machine Learning Algorithms
Stratifying prognosis following coronary bifurcation percutaneous coronary intervention (PCI) is an unmet clinical need that may be fulfilled through the adoption of machine learning (ML) algorithms to refine outcome predictions. We sought to develop an ML-based risk stratification model built on clinical, anatomical, and procedural features to predict all-cause mortality following contemporary bifurcation PCI. Multiple ML models to predict all-cause mortality were tested on a cohort of 2393 patients (training, n = 1795; internal validation, n = 598) undergoing bifurcation PCI with contemporary stents from the real-world RAIN registry. Twenty-five commonly available patient-/lesion-related features were selected to train ML models. The best model was validated in an external cohort of 1701 patients undergoing bifurcation PCI from the DUTCH PEERS and BIO-RESORT trial cohorts. At ROC curves, the AUC for the prediction of 2-year mortality was 0.79 (0.74–0.83) in the overall population, 0.74 (0.62–0.85) at internal validation and 0.71 (0.62–0.79) at external validation. Performance at risk ranking analysis, k-center cross-validation, and continual learning confirmed the generalizability of the models, also available as an online interface. The RAIN-ML prediction model represents the first tool combining clinical, anatomical, and procedural features to predict all-cause mortality among patients undergoing contemporary bifurcation PCI with reliable performance
Entanglement evolution and generalised hydrodynamics: noninteracting systems
The large-scale properties of homogeneous states after quantum quenches in integrable systems have been successfully described by a semiclassical picture of moving quasiparticles. Here we consider the generalisation for the entanglement evolution after an inhomogeneous quench in noninteracting systems in the framework of generalised hydrodynamics. We focus on the protocol where two semi-infinite halves are initially prepared in different states and then joined together, showing that a proper generalisation of the quasiparticle picture leads to exact quantitative predictions. If the system is initially prepared in a quasistationary state, we find that the entanglement entropy is additive and it can be computed by means of generalised hydrodynamics. Conversely, additivity is lost when the initial state is not quasistationary; yet the entanglement entropy in the large-scale limit can be exactly predicted in the quasiparticle picture, provided that the initial state is low entangled
Quasi-local conserved charges and spin transport in spin-1 integrable chains
We consider the integrable one-dimensional spin-1 chain defined by the Zamolodchikov-Fateev (ZF) Hamiltonian. The latter is parametrized, analogously to the XXZ spin-1/2 model, by a continuous anisotropy parameter and at the isotropic point coincides with the well-known spin-1 Babujian-Takhtajan Hamiltonian. Following a procedure recently developed for the XXZ model, we explicitly construct a continuous family of quasi-local conserved operators for the periodic spin-1 ZF chain. Our construction is valid for a dense set of commensurate values of the anisotropy parameter in the gapless regime where the isotropic point is excluded. Using the Mazur inequality, we show that, as for the XXZ model, these quasi-local charges are enough to prove that the high-temperature spin Drude weight is non-vanishing in the thermodynamic limit, thus establishing ballistic spin transport at high temperature
- …