186 research outputs found
A nonlocal phase-field model of Ginzburg-Landau-Korteweg fluids
A thermodynamic model of Korteweg fluids undergoing phase transition and/or phase separation
is developed within the framework of weakly nonlocal thermodynamics. Compatibility with second law of
thermodynamics is investigated by applying a generalized Liu procedure recently introduced in the literature.
Possible forms of the free energy and of the stress tensor, which generalize some earlier ones proposed by
several authors in the last decades, are carried out. Owing to the new procedure applied for exploiting the
entropy principle, the thermodynamic potentials are allowed to depend on the whole set of variables spanning
the state space, including the gradients of the unknown fields, without postulating neither the presence of an
energy or entropy extra-flux, nor an additional balance law for microforce
Risk factors for obstructive sleep apnea syndrome in children: state of the art
The obstructive sleep apnea syndrome (OSAS) represents only part of a large group of pathologies of variable entity called respiratory sleep disorders (RSD) which include simple snoring and increased upper airway resistance syndrome (UARS). Although the etiopathogenesis of adult OSAS is well known, many aspects of this syndrome in children are still debated. Its prevalence is about 2% in children from 2 to 8 years of age, mostly related to the size of the upper airways adenoid tissue. Several risk factors linked to the development of OSAS are typical of the pediatric age. The object of this paper is to analyze the state of the art on this specific topic, discussing its implications in terms of diagnosis and management
A formalism to compare electrocatalysts for the oxygen reduction reaction by cyclic voltammetry with the thin-film rotating ring-disk electrode measurements
This report describes a general method to correlate the features determining the performance of an electrocatalyst (EC), including the accessibility of O2 to the active sites and the kinetic activation barrier, with the outcome of conventional electrochemical experiments. The method has been implemented for oxygen reduction reaction ECs by cyclic voltammetry with the thin-film rotating ring-disk electrode setup. The method (i) does not rely on the simplifications associated with the Butler-Volmer kinetic description of electrochemical processes and (ii) does not make assumptions on the specific features of the EC, allowing to compare accurately the kinetic performance of oxygen reduction reaction ECs with completely different chemistry. Finally, with respect to other widespread figures of merit (e.g. the half-wave potential E1/2), the figure of merit here proposed, for example, E(jPt[5%]), allows for much more accurate comparisons of the kinetic performance of ECs
Lâindustrializzazione dellâagricoltura nella Piana del Sele: una prospettiva geografica basata sullâUrban Atlas Copernicus
Il contributo nasce da un approccio interdisciplinare allo studio delle tra-sformazioni territoriali: ne sono autori, infatti, geografi, fisici e ingegneri ambientali esperti di telerilevamento.
Lâobiettivo Ăš quello di studiare la recente espansione del capitalismo agricolo in una regione strategica per lâeconomia del Mezzogiorno: la Piana del Sele. In pochi anni, questo territorio a forte vocazione agri-cola ha conosciuto una drastica alterazione della copertura del suolo, che, se nel 2012 registrava un sostanziale equilibrio tra seminativi e serre, nel 2018, in appena sei anni, ha visto una crescita ponderosa delle serre a scapito proprio dei seminativi. Ă questa la conseguen-za dellâespansione della cosiddetta âquarta gammaâ nel mercato or-tofrutticolo - esplosa anche in Italia nelle ultime due decadi â ovvero la produzione in serra di prodotti freschi, lavati e pronti al consumo. Si tratta di un fenomeno che, oltre alla valenza commerciale, ha dei riverberi geo-economici, sociali e ambientali di primâordine. In primo luogo, la penetrazione nei mercati locali dei grandi capitalisti agricoli; in secondo luogo, la riduzione della capacitĂ degli ecosistemi di assi-curare beni e servizi; in terzo luogo, il depauperamento del paesaggio e il potenziale aumento del rischio idrogeologico.
La metodologia dâindagine prevede lâanalisi dei cambiamenti del-la land cover nei comuni di Battipaglia e Bellizzi, nella provincia di Salerno, nel segmento temporale 2012-2018 attraverso lâUrban Atlas Copernicus, realizzato utilizzando dati satellitari ad altissima risolu-zione. Attraverso il software InVEST, ai cambiamenti osservati Ăš stata abbinata la quantificazione della perdita generata dalla riduzione dei beni e servizi ecosistemici.ritorial transformations: in fact, its authors are geographers, physicists and environmental engineers who are experts in remote sensing.
The aim is to study the recent expansion of agricultural capitalism in a strategic region for the economy of the South: the Sele Plain. In just a few years, this territory with a strong agricultural vocation has experienced a drastic alteration of the land cover: in 2012 there was a substantial bal-ance between arable land and greenhouses, but in 2018, in just six years, there was a substantial growth of greenhouses own detriment of arable land. This is the consequence of the expansion of the so-called âfourth rangeâ in the fruit and vegetable market - which has also grown up in Italy in the last two decades - or rather the greenhouse production of fresh, washed and ready-to-eat products. It is a phenomenon which, in addition to its commercial value, has first-rate geo-economic, social and environmental effects. First, the penetration of local markets by large ag-ricultural capitalists; secondly, the reduction of the ability of ecosystems to provide goods and services; thirdly, the depletion of the landscape and the potential increase in hydrogeological risk.
The survey methodology involves the analysis of land cover changes in the municipalities of Battipaglia and Bellizzi, in the province of Salerno, in the 2012-2018 time span through the Urban Atlas Copernicus, created using very high resolution satellite data. Through the InVEST software, the observed changes were combined with the quantification of the loss generated by the reduction of the ecosystem goods and services
Oxidative stress and inflammation biomarker expression in obstructive sleep apnea patients
Obstructive Sleep Apnea Syndrome (OSAS) is a respiratory sleep disorder characterised by repeated episodes of partial or complete obstruction of the upper airway during the night. This obstruction usually occurs with a reduction (hypopnea) or complete cessation (apnea) of the airflow in the upper airways with the persistence of thoracic-diaphragmatic respiratory movements. During the hypopnea/apnea events, poor alveolar ventilation reduces the oxygen saturation in the arterial blood (SaO2) and a gradual increase in the partial arterial pressure of carbon dioxide (PaCO2). The direct consequence of the intermittent hypoxia is an oxidative imbalance, with reactive oxygen species production and the inflammatory cascade's activation with pro and anti-inflammatory cytokines growth. Tumour necrosis factors, inflammatory cytokines (IL2, IL4, IL6), lipid peroxidation, and cell-free DNA have been found to increase in OSAS patients. However, even though different risk-related markers have been described and analysed in the literature, it has not yet been clarified whether specified inflammatory bio-markers better correlates with OSAS diagnosis and its clinical evolution/comorbidities. We perform a scientific literature review to discuss inflammatory and oxidative stress biomarkers currently tested in OSAS patients and their correlation with the disease's severity and treatment
Laryngopharyngeal reflux diagnosis in obstructive sleep apnea patients using the pepsin salivary test
Background: To investigate the presence of laryngopharyngeal reflux in
patients with obstructive sleep apnea (OSA) employing the salivary pepsin
concentration method. To compare the results of pepsin concentration with the
severity of the pathology. Methods: Seventy-five OSA patients (44 males, 31
females) were enrolled in the study. For each patient, the AHI (apneaâhypopnea
index) and the BMI (body mass index) were initially evaluated. All the patients
enrolled were assessed using the reflux symptom index (RSI) and the reflux finding
score (RFS) in order to perform a clinical diagnosis of laryngopharyngeal reflux. In
all patients a salivary sample was taken to estimate the presence of pepsin and its
concentration. Results: The incidence of LPR (laryngopharyngeal reflux) in OSA
patients, evaluated using the salivary pepsin concentration test (PEP-test), was
found to be 32% of cases. Linear regression testing did not show any correlation
between AHI and pepsin concentration in salivary samples (p = 0.1). Conclusion: A
high number of patients with OSA seem to show positivity for salivary pepsin,
correlated to an LPR. There does not appear to be a correlation between the severity
of apnea and the grade of salivary pepsin reflux. On the other hand, direct correlation between BMI and the value of pepsin in salivary specimens was
observed
The instrument control unit of the AIRS instrument on-board the ARIEL mission: design status after PDR
ARIEL (Atmospheric Remote-sensing InfraRed Large-survey) is the fourth medium-class mission (M4) of the European Space Agency, part of the Cosmic Vision program, whose launch is planned by late 2029. ARIEL aims to study the composition of exoplanet atmospheres, their formation and evolution. The ARIELâs target will be a sample of about 1000 planets observed with one or more of the following methods: transit, eclipse and phase-curve spectroscopy, in both visible and infrared light. The scientific payload is composed by a reflective telescope having a 1m-class elliptical primary mirror, built in solid Aluminum, and two focal-plane instruments: FGS and AIRS. FGS (Fine Guidance System)3 has the double purpose of performing photometry (0.50-0.55 ”m) and low resolution spectrometry over three bands (from 0.8 to 1.95 ”m) and, simultaneously, to provide data to the spacecraft AOCS (Attitude and Orbit Control System). AIRS (ARIEL InfraRed Spectrometer) instrument will perform IR spectrometry in two wavelength ranges: between 1.95 and 3.9 ”m (with a spectral resolution R > 100) and between 3.9 and 7.8 ”m with a spectral resolution R > 30. This paper provides the status of the ICU (Instrument Control Unit), an electronic box whose purpose is to command and supply power to the AIRS warm front-end (as well as acquire science data from its two channels) and to command and control the TCU (Telescope Control Unit)
Genetic determinants in a critical domain of ns5a correlate with hepatocellular carcinoma in cirrhotic patients infected with hcv genotype 1b
HCV is an important cause of hepatocellular carcinoma (HCC). HCV NS5A domainâ1 interacts with cellular proteins inducing proâoncogenic pathways. Thus, we explore genetic variations in NS5A domainâ1 and their association with HCC, by analyzing 188 NS5A sequences from HCV genotypeâ1b infected DAAânaĂŻve cirrhotic patients: 34 with HCC and 154 without HCC. Specific NS5A mutations significantly correlate with HCC: S3T (8.8% vs. 1.3%, p = 0.01), T122M (8.8% vs. 0.0%, p < 0.001), M133I (20.6% vs. 3.9%, p < 0.001), and Q181E (11.8% vs. 0.6%, p < 0.001). By multivariable analysis, the presence of >1 of them independently correlates with HCC (OR (95%CI): 21.8 (5.7â82.3); p < 0.001). Focusing on HCCâgroup, the presence of these mutations correlates with higher viremia (median (IQR): 5.7 (5.4â6.2) log IU/mL vs. 5.3 (4.4â5.6) log IU/mL, p = 0.02) and lower ALT (35 (30â71) vs. 83 (48â108) U/L, p = 0.004), suggesting a role in enhancing viral fitness without affecting necroinflammation. Notably, these mutations reside in NS5A regions known to interact with cellular proteins crucial for cellâcycle regulation (p53, p85âPIK3, and ÎČâ catenin), and introduce additional phosphorylation sites, a phenomenon known to ameliorate NS5A interaction with cellular proteins. Overall, these results provide a focus for further investigations on molecular bases of HCVâmediated oncogenesis. The role of these NS5A domainâ1 mutations in triggering proâoncogenic stimuli that can persist also despite achievement of sustained virological response deserves further investigation
The Ariel payload electrical and electronic architecture: a summary of the current design and implementation status
Ariel is the M4 mission of the ESAâs Cosmic Vision Program 2015-2025, whose aim is to characterize by lowresolution transit spectroscopy the atmospheres of over one thousand warm and hot exoplanets orbiting nearby stars. It has been selected by ESA in March 2018 and adopted in November 2020 to be flown, then, in 2029. It is the first survey mission dedicated to measuring the chemical composition and thermal structures of the atmospheres of hundreds of transiting exoplanets, in order to enable planetary science far beyond the boundaries of the Solar System. The Payload (P/L) is based on a cold section (PLM â Payload Module) working at cryogenic temperatures and a warm section, located within the Spacecraft (S/C) Service Vehicle Module (SVM) and hosting five warm units operated at ambient temperature (253-313 K). The P/L and its electrical, electronic and data handling architecture has been designed and optimized to perform transit spectroscopy from space during primary and secondary planetary eclipses in order to achieve a large set of unbiased observations to shed light and fully understand the nature of exoplanets atmospheres, retrieving information about planets interior and determining the key factors affecting the formation and evolution of planetary systems
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