Phase-averaged characterization of turbulent isothermal free swirling jet after vortex breakdown

This work mainly focused on the near-exit region of a round isothermal free swirling jet to characterize the effect of swirl on the flow field and to identify large coherent structures. 3C-2D PIV was employed to capture the instantaneous flow field close to the nozzle exit for non-swirling (S=0) and a high swirling jets (S=1.26) both with a Reynolds number of 21800. At swirl level of 1.26 the pressure fluctuations measured by a capacitive microphone indicate the existence of periodic instability, the so called precessing vortex core (PVC). A three-component proper orthogonal decomposition (POD) applied to the instantaneous velocity fields allow to identify the dominant flow structure associated to the PVC. The time coefficients of the two first most energetic POD modes were used to reconstruct the phase of the oscillatory motion in the swirling flow. The phase information was then used to conditionally average the instantaneous velocity field s, this allowed the 3D structure of the PVC to be reconstructed. The instantaneous minima of negative swirling strength values calculated from the instantaneous velocity field revealed the presence of two helical structures located in the inner and outer shear layers. By phase averaging the instantaneous swirling strength maps, the 3D helical vortex structure was reconstructed . The two co-winding counter-rotating helical structure fade out at an axial location of approximately z/ D = 1.5. The findings evidence that the combined application of PIV, POD and frequency analysis using capacitive microphone can provide detailed observations of coherent fluctuations ind uced by vortex precession

AN EXPERIMENTAL INVESTIGATION ON ISOTHERMAL FREE SWIRLING JET

This paper reports an experimental investigation on the dynamics of turbulent unconfined swirling flows. Isothermal free swirling jets with five different swirl numbers (S) and fixed Reynolds number (Re = 21800) are investigated to analyze the effect of swirl intensity on the recirculation, vortex breakdown and the occurrence of the precession vortex core (PVC) by means of 3C-2D Stereoscopic Particle image velocimetry (PIV). The contours and radial profiles of mean axial velocity confirmed the central recirculation zone (CRZ) for high swirl number. The importance of central recirculation zone is to ensure a good mixing of air/ fuel and combustion products and to generate a low velocity region for flame stabilization. Results shows that swirl intensity increases the backflow rate in the recirculation zone and jet spreads almost linearly with a higher spread rate as compared to non swirling flow. The frequency characteristics have been measured with a capacitive microphone. The frequency spectrum indicates the presence of periodic oscillation related to the existence of PVC. The Strouhal number associated with the frequency of the PVC vary almost linearly with swirl intensity

DMD Analysis of Experimental PIV Data of a Swirled Jet

This paper concerns the study of high Reynolds and high swirl number flow through the use of PIV measurements and Dynamic Mode Decomposition (DMD) analysis. Principles governing DMD are briefly recalled, then the use of DMD is demonstrated by analysing the acquired PIV data in order to study the dominant dynamics of the system and extracting relevant morphology via DMD modes, focusing the attention on phenomenon known as Precessing Vortex Core (PVC)

Metabolomic Changes in Patients Affected by Multiple Sclerosis and Treated with Fingolimod

Current treatment for Multiple Sclerosis (MS) consists of a multidisciplinary approach including disease-modifying therapies. The response to treatment is heterogeneous, representing a crucial challenge in the classification of patients. Metabolomics is an innovative tool that can identifies biomarkers/predictors of treatment response. We aimed to evaluate plasma metabolic changes in a group of naïve Relapsing-Remitting MS patients starting Fingolimod treatment, to find specific metabolomic features that predict the therapeutic response as well as the possible side effects. The study included 42 Relapsing-Remitting MS blood samples, of which 30 were classified as responders after two years of FINGO treatment, whereas 12 patients were Not-Responders. For fifteen patients, samples were collected at four time points: before starting the therapy; at six months after the initiation; at twelve months after; and at twenty-four months after initiation. The serum was analysed through Nuclear Magnetic Resonance and multivariate and univariate statistical analysis. Considering the single comparison between each time point, it was possible to identify a set of metabolites changing their concentrations based on the drug intake. FINGO influences aminoacidic and energy metabolisms and reduces oxidative stress and the activity of the immune system, both typical features of MS

Brain Volume and Perception of Cognitive Impairment in People With Multiple Sclerosis and Their Caregivers

Background: Cognitive impairment (CI) is common in people with multiple sclerosis (pwMS). The assessment of CI is based on neuropsychological tests and accurate anamnesis, involving the patients and caregivers (CG). This study aimed to assess the complex interplay between self-perception of CI, objective CI and the brain atrophy of MS patients, also exploring the possible differences with CI evaluated by caregivers. Methods: Relapsing pwMS were enrolled in this study. Subjects underwent neuropsychological examination using the Brief Cognitive Assessment for Multiple Sclerosis (BICAMS) and evaluation of self-reported cognitive status using the patient-version of the Multiple Sclerosis Neuropsychological Questionnaire (p-MSNQ). Depression and anxiety were also evaluated using the Back Depression Inventory-version II (BDI-II) and Zung Anxiety Scale. Brain MRI images were acquired and brain volumes estimated. For each patient that was enrolled, we spoke to a caregiver and collected their perception of the patient's CI using the MSNQ- Caregiver version. Results: Ninety-five MS subjects with their caregivers were enrolled. CI was detected in 51 (53.7%) patients. We found a significant correlation (p < 0.001) between BICAMS T scores and lower whole brain (Rho = 0.51), gray matter (Rho = 0.54), cortical gray matter (Rho = 0.51) volumes and lower p-MSNQ (Rho = 0.31), and cg-MSNQ (Rho = 0.41) scores. Multivariate logistic regression showed that p-MSNQ is related to a patient's anxiety to evaluate by Zung Score (p < 0.001) while cg-MSNQ to patient's brain volume (p = 0.01). Conclusion: Our data confirm that neuropsychological evaluation results are related to the perception of CI and brain volume measures and highlight the importance of the caregiver's perception for cognitive assessment of pwMS

Studio del deficit di alfa-1 antitripsina nella popolazione Sarda

Introduzione: L’ AATD e’ una forma genetica abbastanza comune di malattia epatica nel bambino e di enfisema polmonare ed epatopatia nell’adulto, pur facendo parte delle malattie rare. Si manifesta spesso con sintomatologia clinica aspecifica, con tempi e modalità variabili, e spesso non sono utilizzati i test molecolari per una diagnosi definitiva. La diagnosi di laboratorio è spesso casuale e può essere posta partendo dall’assenza del picco delle α1-globuline all’ESP. Tale carenza induce a sospettare l’AATD, che deve essere prima confermata con il dosaggio sierico e quando necessario deve essere studiato il profilo genico. Per questi motivi, è ragionevole pensare che l’AATD sia una condizione clinica sottostimata, da considerarsi probabilmente non una malattia rara, ma raramente diagnosticata. In Sardegna i casi di AATD sono correlati ad una mutazione nota come M-Malton/ M-Cagliari, rarissima nelle altre popolazioni, o alla mutazione S. Non disponiamo ancora di dati attendibili circa la frequenza di questa mutazione. Scopo del lavoro è quello di individuare i soggetti con AATD e calcolare la frequenza della mutazione nella popolazione da noi considerata, trovare un cut-off decisionale di laboratorio da utilizzare per stabilire quali pazienti studiare per la mutazione

USE OF GAS CHROMATOGRAPHY ORAL CHROMA™ IN THE ASSESSMENT OF VOLATILE SULFUR COMPOUNDS FOR BREATH’S ANALYSIS IN ORAL AND GASTRIC AFFECTION

Introduction: Breathomics (Breath-based metabolomics) is a new biotechnology approach that allow us to diagnose some human diseases by the oral breath analysis.The method is based on the identi#cation and quanti#cation of volatile organic compound (VOC) in breath, by a new portable gas chromatography’s tools such as Oral Chroma®. This instrument is able to detect and quantify three different volatile sulfur compounds, VSC ( H2S, CH3S ,(CH3)2S) in 5 ml of oral breath, in fast time and with good analytical accuracy. In addition, different authors recently have been described as a comparative analysis of VSC could be useful in the diagnosis of different oral or systemic diseases such as: (i) oral tongue halitosis or/and gastric affection such as Helicobacter pylori infectio

Immunohistochemical findings in the lungs of COVID-19 subjects: Evidence of surfactant dysregulation

OBJECTIVE: Acute respiratory distress syndrome (ARDS) is characterized by quantitative and qualitative changes in surfactant composition, leading to surfactant dysregulation with alveolar collapse and acute respiratory hypoxic failure. Recently, surfactant has been hypothesized to play a relevant role in COVID-19, representing a strong defender against SARSCoV-2 infection. The aim of our work was the study of immunohistochemical surfactant expression in the lungs of patients died following SARS-CoV-2 ARDS, in order to shed light on a possible therapeutic surfactant administration. PATIENTS AND METHODS: We investigated four patients who died due to ARDS following SARS-COV-2 infection and four patients submitted to lung biopsy, in the absence of SARSCoV-2 infection. In all 8 cases, lung specimens were immunostained with anti-surfactant protein A (SP-A) and B (SP-B). RESULTS: In control subjects, reactivity for SP-B was restricted to type II alveolar cells. Immunostaining for SP-A was observed on the surface of alveolar spaces. In the COVID-19 positive lungs, immunoreactivity for SP-B was similar to that observed in control lungs; SP-A was strongly expressed along the alveolar wall. Moreover, dense aggregates of SP-A positive material were observed in the alveolar spaces. CONCLUSIONS: Our immunohistochemical data show the dysregulation of surfactant production in COVID-19 patients, particularly regarding SP-A expression. The increased presence of SP-A in condensed masses inside alveolar spaces could invalidate the therapeutic efficacy of the treatment with exogenous surfactant

Interindividual variability in L1CAM expression in the human kidney during development: are there implications for fetal programming of kidney diseases presenting in adulthood?

L1 cell adhesion molecule (L1CAM) is a member of the immunoglobulin superfamily of cell adhesion molecules. The present study investigated the expression of L1CAM during the development in the fetal human kidney at different gestational ages, to reach a better knowledge on the role of L1CAM in renal morphogenesis