Unsteady Separation and Navier-Stokes Solutions at High Reynolds Numbers

2010

We compute the numerical solutions for Navier-Stokes and Prandtl’s equations in the case of a uniform bidimensional flow past an impulsively started disk. The numerical approx- imation is based on a spectral methods imple- mented in a Grid environment. We investigate the relationship between the phenomena of unsteady separation of the flow and the exponential decay of the Fourier spectrum of the solutions. We show that Prandtl’s solution develops a separation singularity in a finite time. Navier-Stokes solutions are computed over a range of Reynolds numbers from 3000 to 50000. We show that the appearance of large gradients of the pressure in the stream- wise direction, reveals that the visc…

Symmetry reduction of a model in spherical symmetry for the radiation hydrodynamics in general relativity

2004

A Subcritical Bifurcation for a Nonlinear Reaction–Diffusion System

2010

In this paper the mechanism of pattern formation for a reaction-diffusion system with nonlinear diffusion terms is investigated. Through a linear stability analysis we show that the cross-diffusion term allows the pattern formation. To predict the form and the amplitude of the pattern we perform a weakly nonlinear analysis. In the supercritical case the Stuart-Landau equation is found, which rules the evolution of the amplitude of the most unstable mode. With the increasing distance from the bifurcation value of the cross-diffusion parameter, the weakly nonlinear analysis fails and a Fourier–Galerkin approach is adopted. In the subcritical case the weakly nonlinear analysis must be pushed u…

On a radiating fluid in a general relativistic context

2006

A model for the radiation hydrodynamics in general relativity is analyzed, describing the gravitational collapse and supernovae explosion. As these physical phenomena can be assumed spherically symmetric, the equations of motion for a unique fluid, representing the interaction between matter and radiation, are written in a spherical symmetric space-time with respect to a comoving frame. The system is completed by using the Eddington closure, assuming a local thermodynamical equilibrium for the radiation field. The resulting system is analyzed by the Lie symmetry approach and a reduction to an ODEs system is obtained. Numerical simulations of the solutions are performed, showing a realistic …

Deep Learning Networks for Automatic Retroperitoneal Sarcoma Segmentation in Computerized Tomography

2022

The volume estimation of retroperitoneal sarcoma (RPS) is often difficult due to its huge dimensions and irregular shape; thus, it often requires manual segmentation, which is time-consuming and operator-dependent. This study aimed to evaluate two fully automated deep learning networks (ENet and ERFNet) for RPS segmentation. This retrospective study included 20 patients with RPS who received an abdominal computed tomography (CT) examination. Forty-nine CT examinations, with a total of 72 lesions, were included. Manual segmentation was performed by two radiologists in consensus, and automatic segmentation was performed using ENet and ERFNet. Significant differences between manual and automat…

Qualitative mucin disorders in patients with primary Sjögren's syndrome:a literature review

2020

Background It is a common opinion that Primary Sjögren Syndrome (pSS) damages the exocrine glands and determines the reduction of secreted saliva, some studies show that there are qualitative anomalies of the mucins produced in saliva, including MUC7, MUC5B, MUC1. The purpose of this study is to trace all the information useful to establish whether there is a qualitative or quantitative defect of the mucins in the pSS. Material and Methods We reviewed the literature by looking for publications relevant to the topic in electronic databases. Sixteen articles met the search criteria. The studies were divided into two categories, those that studied the rheological characteristics of the saliva …

Older women are frailer, but less often die then men: a prospective study of older hospitalized people

2019

Abstract Objectives The association between frailty, mortality and sex is complex, but a limited literature is available on this topic, particularly for older hospitalized patients. Therefore, the objective of our study was to prospectively evaluate sex differences in frailty, assessed by the Multidimensional Prognostic Index (MPI) and mortality, institutionalization, and re-hospitalization in an international cohort of older people admitted to hospital. Study design We used data from nine public hospitals in Europe and Australia, to evaluate sex differences in mortality, frailty and the risk of institutionalization and re-hospitalization, during one year of follow-up. Main outcome measures…

The Prevalence of Chronic Cerebrospinal Venous Insufficiency in Meniere Disease: 24-Month Follow-up after Angioplasty

2016

Abstract Purpose To evaluate relationship between Meniere disease (MD) and chronic cerebrospinal venous insufficiency (CCSVI) using ultrasound, magnetic resonance (MR) imaging, and venography and to evaluate the effectiveness of angioplasty of the internal jugular vein (IJV) and azygos vein (AV) in reducing symptoms of MD. Materials and Methods Patients with a confirmed diagnosis of MD unresponsive to standard treatment underwent duplex ultrasound and MR imaging to diagnose CCSVI. Healthy volunteers were also studied to evaluate CCSVI in asymptomatic subjects. Patients with CCSVI and MD underwent venography and percutaneous transluminal angioplasty (PTA) of IJV and AV. Results There were 18…

Extended thermodynamics and superfluidity

1984

Exploitation des consequences de la thermodynamique generalisee en appliquant ses equations a un gaz de Bose degenere ou la condensation de Bose-Einstein a lieu. Formes particulieres de ces equations, qui gouvernent la dissipation, pour 4 He. Equation du second son

I-MALL An Effective Framework for Personalized Visits. Improving the Customer Experience in Stores

2022

In this paper we present I-MALL, an ICT hardware and software infrastructure that enables the management of services related to places such as shopping malls, showrooms, and conferences held in dedicated facilities. I-MALL offers a network of services that perform customer behavior analysis through computer vision and provide personalized recommendations made available on digital signage terminals. The user can also interact with a social robot. Recommendations are inferred on the basis of the profile of interests computed by the system analysing the history of the customer visit and his/her behavior including information from his/her appearance, the route taken inside the facility, as well…

Enzymatic Spermine Metabolites Induce Apoptosis Associated with Increase of p53, caspase-3 and miR-34a in Both Neuroblastoma Cells, SJNKP and the N-M…

2021

Neuroblastoma (NB) is a common malignant solid tumor in children and accounts for 15% of childhood cancer mortality. Amplification of the N-Myc oncogene is a well-established poor prognostic marker in NB patients and strongly correlates with higher tumor aggression and resistance to treatment. New therapies for patients with N-Myc-amplified NB need to be developed. After treating NB cells with BSAO/SPM, the detection of apoptosis was determined after annexin V-FITC labeling and DNA staining with propidium iodide. The mitochondrial membrane potential activity was checked, labeling cells with the probe JC-1 dye. We analyzed, by real-time RT-PCR, the transcript of genes involved in the apoptot…

Radiomics Analyses of Schwannomas in the Head and Neck: A Preliminary Analysis

2022

The purpose of this preliminary study was to evaluate the differences in Magnetic Resonance Imaging (MRI)-based radiomics analysis between cerebellopontine angle neurinomas and schwannomas originating from other locations in the neck spaces. Twenty-six patients with available MRI exams and head and neck schwannomas were included. Lesions were manually segmented on the precontrast and postcontrast T1 sequences. The radiomics features were extracted by using PyRadiomics software, and a total of 120 radiomics features were obtained from each segmented tumor volume. An operator-independent hybrid descriptive‐inferential method was adopted for the selection and reduction of the features, while d…

Enteral tube feeding and mortality in hospitalized older patients: A multicenter longitudinal study

2020

Background & aims: The literature regarding enteral nutrition and mortality in older frail people is limited and still conflicting. Moreover, the potential role of comprehensive geriatric assessment is poorly explored. We therefore aimed to investigate whether the Multidimensional Prognostic Index (MPI), an established tool that assesses measures of frailty and predicts mortality, may help physicians in identifying patients in whom ETF (enteral tube feeding) is effective in terms of reduced mortality. Methods: Observational, longitudinal, multicenter study with one year of follow-up. Data regarding ETF were recorded through medical records. A standardized comprehensive geriatric assessm…

Recent advances and disputes about curcumin in retinal diseases

2021

Abstract Curcumin belongs to the group of so-called phytocompounds, biologically active molecules produced by plants exerting a beneficial effect on health. Curcumin shows a wide spectrum of different properties, being an anti-inflammatory, antioxidant, antimicrobial and antimutagenic molecule. The purpose of the review is to examine what literature reported on the characteristics of curcumin, particularly, on the beneficial and controversial aspects of this molecule, aiming for a better therapeutic management of retinal diseases. The retina is a constant target of oxidative stress, this tissue being characterized by cells rich in mitochondria and by vessels and being, obviously, continuous…

Interaction of Gravitational and Fluid Waves

2009

A particle method for a Lotka-Volterra system with nonlinear cross and self-diffusion

2008

Drug Prescription and Delirium in Older Inpatients: Results From the Nationwide Multicenter Italian Delirium Day 2015-2016

2019

Objective This study aimed to evaluate the association between polypharmacy and delirium, the association of specific drug categories with delirium, and the differences in drug-delirium association between medical and surgical units and according to dementia diagnosis. Methods Data were collected during 2 waves of Delirium Day, a multicenter delirium prevalence study including patients (aged 65 years or older) admitted to acute and long-term care wards in Italy (2015-2016); in this study, only patients enrolled in acute hospital wards were selected (n = 4,133). Delirium was assessed according to score on the 4 "A's" Test. Prescriptions were classified by main drug categories; polypharmacy w…

Unsteady Separation for High Reynolds Numbers Navier-Stokes Solutions

2010

In this paper we compute the numerical solutions of Navier-Stokes equations in the case of the two dimensional disk impulsively started in a uniform back- ground flow. We shall solve the Navier-Stokes equations (for different Reynolds numbers ranging from 1.5 · 10^3 up to 10^5 ) with a fully spectral numerical scheme. We shall give a description of unsteady separation process in terms of large and small scale interactions acting over the flow. The beginning of these interactions will be linked to the topological change of the streamwise pressure gradient on the disk. Moreover we shall see how these stages of separation are related to the complex singularities of the solution. Infact the ana…

Transition to turbulence and Singularity in Boundary Layer Theory

2007

We compute the solutions of Prandtl’s and Navier- Stokes equations for the two dimensional flow induced by an array of periodic rectilinear vortices interacting with a boundary in the halfplane. This initial datum develops, in a finite time, a separation singularity for Prandtl’s equation. We investigate the different stages of unsteady separation in Navier-Stokes solutions for various Reynolds numbers. We show the presence of a large- scale interaction between viscous boundary layer and inviscid outer flow in all Re regimes, while the presence of a small-scale interaction is visible only for moderate-high Re numbers. We also investigate the asymptotic validity of boundary layer theory in t…