74 research outputs found
Multi-domain analysis and prediction of the light emitted by an inductively coupled plasma jet
Inductively coupled plasma wind tunnels are crucial for replicating
hypersonic flight conditions in ground testing. Achieving the desired
conditions (e.g., stagnation-point heat fluxes and enthalpies during
atmospheric reentry) requires a careful selection of operating inputs, such as
mass flow, gas composition, nozzle geometry, torch power, chamber pressure, and
probing location along the plasma jet. The study presented herein focuses on
the influence of the torch power and chamber pressure on the plasma jet
dynamics within the 350 kW Plasmatron X ICP facility at the University of
Illinois at Urbana-Champaign. A multi-domain analysis of the jet behavior under
selected power-pressure conditions is presented in terms of emitted light
measurements collected using high-speed imaging. We then use Gaussian Process
Regression to develop a data-informed learning framework for predicting
Plasmatron X jet profiles at unseen pressure and power test conditions.
Understanding the physics behind the dynamics of high-enthalpy flows,
particularly plasma jets, is the key to properly design material testing,
perform diagnostics, and develop accurate simulation modelsComment: 22 pages (including figures, appendix, and references); 13 figure
Optical-flow-based motion compensation algorithm in thermoelastic stress analysis using single-infrared video
Thermoelastic stress analysis (TSA) is a non-contact measurement technique for stress distribution evaluation. A common issue related to this technique is the rigid-displacement of the specimen during the test phase, that can compromise the reliability of the measurement. For this purpose, several motion compensation techniques have been implemented over the years, but none of them is provided through a single measurement and a single sample surface conditioning. Due to this, a motion compensation technique based on Optical-Flow has been implemented, which greatly increases the strength and the effectiveness of the methodology through a single measurement and single specimen preparation. The proposed approach is based on measuring the displacement field of the specimen directly from the thermal video, through optical flow. This displacement field is then used to compensate for the specimen's displacement on the infrared video, which will then be used for thermoelastic stress analysis. Firstly, the algorithm was validated by a comparison with synthetic videos, created ad hoc, and the quality of the motion compensation approach was evaluated on video acquired in the visible range. The research moved into infrared acquisitions, where the application of TSA gave reliable and accurate results. Finally, the quality of the stress map obtained was verified by comparison with a numerical model.</p
Peripheral nervous system involvement in SARS-CoV-2 infection: a review of the current pediatric literature
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the pathogen responsible for the pandemic health emergency declared by the World Health Organization in March 2020. During the first part of the pandemic, adults showed mild to severe respiratory symptoms. Children seemed initially exempt, both from acute and subsequent complications. Hyposmia or anosmia were promptly identified as the main symptoms of acute infection, so neurotropism of SARS-CoV-2 was immediately suspected. (1, 2). As the emergency progressed, post infectious neurological complications were described also in pediatric population (3). Cases of cranial neuropathy in connection with acute SARS-CoV-2 infection have been reported in pediatric patients, as an isolate post infectious complication or in the context of the multisystem inflammatory syndrome in children (MIS-C) (4–6). Neuroinflammation is thought to be caused by several mechanisms, among which immune/autoimmune reactions (7), but so far, no specific autoantibody has been identified. SARS-CoV-2 can enter the central nervous system (CNS) directly and/or infect it retrogradely, through the peripheral nervous system (PNS), after replicating peripherally; several factors regulate invasion and subsequent neuroinflammation. Indeed, direct/secondary entry and replication can activate CNS-resident immune cells that, together with peripheral leukocytes, induce an immune response and promote neuroinflammation. In addition, as we will discuss in the following review, many cases of peripheral neuropathy (cranial and non-cranial) have been reported during or after SARS-CoV-2 infection. However, some authors have pointed out that the increase of cranial roots and ganglia in neurological imaging is not always observed in children with cranial neuropathy. (8). Even if a variety of case reports were published, opinions about an increased incidence of such neurologic diseases, linked to SARS-CoV-2 infection, are still controversial (9–11). Facial nerve palsy, ocular movements abnormalities and vestibular alterations are among the most reported issues in pediatric population (3–5). Moreover, an increased screen exposure imposed by social distancing led to acute oculomotion’s disturbance in children, not primarily caused by neuritis (12, 13). The aim of this review is to suggest food for thought on the role of SARS-CoV-2 in neurological conditions, affecting the peripheral nervous system to optimize the management and care of pediatric patients
Thermoelasticity and ArUco marker-based model validation of polymer structure: application to the San Giorgio's bridge inspection robot
Experimental procedures are often involved in the numerical models validation. To define the behaviour of a structure, its underlying dynamics and stress distributions are generally investigated. In this research, a multi-instrumental and multi-spectral method is proposed in order to validate the numerical model of the Inspection Robot mounted on the new San Giorgio's Bridge on the Polcevera river. An infrared thermoelasticity-based approach is used to measure stress-concentration factors and, additionally, an innovative methodology is implemented to define the natural frequencies of the Robot Inspection structure, based on the detection of ArUco fiducial markers. Established impact hammer procedure is also performed for the validation of the results.</p
Low grade endotoxemia and oxidative stress in offspring of patients with early myocardial infarction
Background and aims: Offspring of patients with early myocardial infarction are at higher cardiovascular risk, but the underlying physio-pathological mechanism is unclear. NADPH oxidase-type 2 (NOX-2) plays a pivotal role as mediator of oxidative stress and could be involved in activating platelets in these patients. Furthermore, altered intestinal permeability and serum lipopolysaccharide (LPS) could be a trigger to promote NOX-2 activation and platelet aggregation. This study aims to evaluate the behavior of low grade endotoxemia, oxidative stress and platelet activation in offspring of patients with early myocardial infarction. Methods: We enrolled, in a cross-sectional study, 46 offspring of patients with early myocardial infarction and 86 healthy subjects (HS). LPS levels and gut permeability (assessed by zonulin), oxidative stress (assessed by serum NOX-2-derived peptide (sNOX2-dp) release, hydrogen peroxide (H2O2) production and isoprostanes), serum nitric oxide (NO) bioavailability and platelet activation (by serum thromboxane B2 (TXB2) and soluble P-Selectin (sP-Selectin)) were analyzed. Results: Compared to HS, offspring of patients with early myocardial infarction had higher values of LPS, zonulin, serum isoprostanes, sNOX2-dp H2O2, TXB2, p-selectin and lower NO bioavailability. Logistic regression analysis showed that the variables associated with offspring of patients with early myocardial infarction were LPS, TXB2 and isoprostanes. The multiple linear regression analysis confirmed that serum NOX-2, isoprostanes, p-selectin and H2O2 levels were significantly associated to LPS. Furthermore, serum LPS, isoprostanes and TXB2 levels were significantly associated with sNOX-2-dp. Conclusions: Offspring of patients with early myocardial infarction have a low grade endotoxemia that could generate oxidative stress and platelet activation increasing their cardiovascular risk. Future studies are needed to understand the role of dysbiosis in this population
Case Report: Interindividual variability and possible role of heterozygous variants in a family with deficiency of adenosine deaminase 2: are all heterozygous born equals?
Deficiency of adenosine deaminase 2 (DADA2) is a rare systemic autoinflammatory disease, typically with autosomal recessive inheritance, usually caused by biallelic loss of function mutations in the ADA2 gene. The phenotypic spectrum is broad, generally including fever, early-onset vasculitis, stroke, and hematologic dysfunction. Heterozygous carriers may show related signs and symptoms, usually milder and at an older age. Here we describe the case of two relatives, the proband and his mother, bearing an ADA2 homozygous pathogenic variant, and a heterozygous son. The proband was a 17-year-old boy with intermittent fever, lymphadenopathies, and mild hypogammaglobulinemia. He also had sporadic episodes of aphthosis, livedo reticularis and abdominal pain. Hypogammaglobulinemia was documented when he was 10 years old, and symptoms appeared in his late adolescence. The mother demonstrated mild hypogammaglobulinemia, chronic pericarditis since she was 30 years old and two transient episodes of diplopia without lacunar lesions on MRI. ADA2 (NM_001282225.2) sequencing identified both mother and son as homozygous for the c.1358A>G, p.(Tyr453Cys) variant. ADA2 activity in the proband and the mother was 80-fold lower than in the controls. Clinical features in both patients improved on anti-tumor necrosis factor therapy. An older son was found to be heterozygous for the same mutation post-mortem. He died at the age of 12 years due to a clinical picture of fever, lymphadenitis, skin rash and hypogammaglobulinemia evolving toward fatal multiorgan failure. Biopsies of skin, lymph nodes, and bone marrow excluded lymphomas and vasculitis. Despite being suspected of symptomatic carrier, the contribution of an additional variant in compound heterozygosity, or further genetic could not be ruled out, due to poor quality of DNA samples available. In conclusion, this familiar case demonstrated the wide range of phenotypic variability in DADA2. The search for ADA2 mutations and the assessment of ADA2 activity should be considered also in patients with the association of hypogammaglobulinemia and inflammatory conditions, also with late presentation and in absence of vasculitis. Furthermore, the clinical picture of the deceased carrier suggests a possible contribution of heterozygous pathogenic variants to inflammation
Diversity and ethics in trauma and acute care surgery teams: results from an international survey
Background Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. Methods The article employs an international questionnaire promoted by the World Society of Emergency Surgery. Results Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. Conclusions Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. Level of evidence Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Utilizzo agronomico del digestato: normative regionali a confronto
La possibilità di utilizzare in campo il digestato (tal quale o, meglio, nelle sue frazioni separate) dipende dal suo inquadramento normativo: nella classificazione di questo prodotto si incontrano diversi provvedimenti, nessuno dei quali però in grado di trattare l’argomento in maniera compiuta e dedicata. In attesa di un atto normativo unico che riesca a fare chiarezza ed a trattare in maniera esaustiva le diverse casistiche verificabili, vi sono alcune condizioni da considerarsi assodate per poter utilizzare in campo il digestato senza sconfinare nell’ambito “rifiuti” e quindi senza dover classificare il suo uso agronomico come operazione di recupero rifiuti, soggetta a specifica autorizzazione.
Quando le matrici organiche in ingresso al digestore sono reflui zootecnici, da soli o in miscela con altre biomasse-non rifiuto, il digestato può essere assimilato agli effluenti animali ed il suo spandimento in campo è assoggettato alle stesse prescrizioni valide per i reflui zootecnici circa tempi di stoccaggio, criteri di spandimento, modalità di trasporto, adempimenti documentali e, soprattutto, dosaggi di nutrienti in zona ordinaria (ZO) e vulnerabile ai nitrati (ZVN). Se invece il digestato è prodotto a partire da una dieta che non contempla gli effluenti animali, si apre lo scenario più controverso quanto ad orientamenti Regionali nella normazione dell’uso agronomico di tale prodotto e nel sostegno alla nascita di impianti di digestione anaerobica a dieta esclusivamente vegetale.
A tale fine, si passa in rassegna l’orientamento delle principali Regioni del Nord Italia (Piemonte, Lombardia, Veneto ed Emilia-Romagna), che stanno operando prevalentemente a sostegno (Emilia-Romagna, Lombardia) o a sfavore (Piemonte e Veneto) del biogas “verde” e quindi dei relativi impianti e sottoprodotti. Si sono in tal modo disegnati scenari anche molto diversi tra loro, in taluni casi non esaustivi, a volte in palese contrasto con gli indirizzi nazionali e comunitari in materia di rifiuti, soprattutto laddove, classificando come rifiuto il digestato derivante, limitano l’ammissibilità in ingresso al bio-digestore di talune tipologie di prodotti e sottoprodotti naturali non pericolosi. Si viene così a creare una disparità di trattamento dello stesso prodotto tra Regioni confinanti, che determina condizioni di maggiore o minore favore per lo sviluppo delle attività agro-energetiche
Applicazioni agronomiche del digestato
Il digestato è il residuo della digestione anaerobica di biomasse vegetali e animali. Si tratta di un prodotto di composizione e consistenza variabili, prevalentemente fluido. Al pari dei liquami zootecnici, non rientra in nessuna delle categorie previste dalla norma che regola la disciplina dei fertilizzanti (D.Lgs. 217/96), il che non ne vincola la possibilità di collocazione attraverso spandimento. Il suo utilizzo è regolato da una complessa legislazione a livello nazionale e regionale, progressivamente apertasi alla possibilità di impiego agronomico.
Le potenzialità agronomico-ambientali derivanti dall’uso del prodotto sono avvalorate da una serie di esperienze sperimentali effettuate in Italia e all’estero. Dal punto di vista agronomico, il digestato ha offerto performance in linea con le caratteristiche del refluo e con i dosaggi saggiati. Ciò è emerso da una rete di prove sperimentali e dimostrative attualmente in corso in Emilia-Romagna, che prevedono il confronto fra digestato e azoto minerale su diverse colture energetiche. Anche all’estero il prodotto si è dimostrato analogo negli effetti fertilizzanti ai liquami, con i vantaggi conseguenti alla produzione di energia, all’eliminazione di odori, ecc..
Dal punto di vista ambientale, ci si è focalizzati sulle emissioni in atmosfera di ammoniaca (NH3), sostanza corresponsabile dei fenomeni di acidificazione ed eutrofizzazione, e sul rilascio di protossido d’azoto (N2O) e metano (CH4), due potenti gas a “effetto serra”. In base alla bibliografia, la somministrazione del digestato aumenta le perdite per volatilizzazione di ammoniaca rispetto ai liquami pre-digestione, mentre contiene l’emissione di N2O dal terreno. Poche sono, invece, le notizie riguardanti le perdite di metano in atmosfera, che sembrano comunque più legate alla fase di stoccaggio che di utilizzo agronomico. L’effetto della digestione dei residui colturali in alternativa al loro interramento si è tradotto anche in una riduzione del contenuto di azoto nitrico del terreno, da cui deriva un più ridotto rischio di lisciviazione, che rappresenta un beneficio aggiuntivo. Prove in corso da parte di chi scrive testimoniano che, con un tempestivo interramento superficiale, anche la volatilizzazione dell’ammoniaca può essere contenuta a pochi punti percentuali.
In conclusione, l’effluente della digestione anaerobica possiede un potere nutritivo non inferiore alle matrici di origine. Il prodotto si presta, inoltre, ad azioni migliorative, come la separazione solido/liquido e l’eventuale compostaggio della prima frazione. A ciò si aggiunge che l’attuale normativa permette un interessante distinguo per l’utilizzo in zone vulnerabili ai nitrati: il limite di 170 kg/ha di N distribuito vale, infatti, solo per la frazione dell’azoto di origine zootecnica, consentendo per la frazione di origine vegetale un dosaggio meno restrittivo
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