A series of primary drainage experiments was carried out in order to investigate nonequilibrium capillarity effects in two‐phase flow through porous media. Experiments were performed with ...tetrachloroethylene (PCE) and water as immiscible fluids in a sand column 21 cm long. Four drainage experiments were performed by applying large pressures on the nonwetting phase at the inlet boundary: 20, 30, 35, 38 kPa. Our results showed that the nonequilibrium local fluids pressure difference‐saturation curves are above the capillary pressure saturation curve. Moreover, the nonequilibrium pressure difference showed a nonmonotonic behavior with an overshoot that was more pronounced at higher injection pressures. The dynamic capillarity coefficient was calculated from measured local pressures and saturations (the scale of sensor devices, 0.7 cm). Its value was found to vary between 1.3 × 105 to 2 × 105 Pa s. Within the saturation range of 0.50 > Sw > 0.85, no clear dependency of the dynamic coefficient on the wetting saturation was observed. Also, no dependency of the dynamic capillarity coefficient on the applied boundary pressure was found. Averaged values of at the length scales of 11 and 18 cm were also estimated from averaged pressures and saturations. The upscaled dynamic coefficient was found to vary between 0.5 × 106 and 1.2 × 106 Pa s at the average window size of 11 cm. This is one order of magnitude larger than the local‐scale coefficient. Larger values were found for the length scale of 18 cm: 1.5 × 106 and 2.5 × 106 Pa s. This suggests that the value of dynamic coefficient increases with the scale of observation.
Key Points
The non‐equilibrium pressure difference shows a non‐monotonic behavior
Pressure difference overshoot is more pronounced at higher injection pressures
The dynamic capillarity coefficient τ is a length scale dependent
Abstract A wide range of environmental pollutants commonly termed endocrine disrupters (ED) can mimic steroid hormones causing adverse health effects. Recent studies showed that bisphenol A (BPA) ...together with other estrogenic chemicals, may be responsible for the disrupting effects observed in fish of the middle River Po. The present study has investigated the potential role of BPA in inducing this kind of effects and to this aim, 1-year-old (k1) common carp were exposed for 14 days to graded concentrations of BPA (1, 10, 100, and 1000 μg/L). Histological alterations of gonads were described and compared to vitellogenin (VTG) and sex steroid levels. In carp males, BPA caused severe alterations of testis structure starting from 1 μg/L. Several specimens lost the typical lobular structure showing spermatogenic cysts intermingled with free spermatozoa often degenerating into the lumen. Oocyte atresia was observed starting from 1 μg BPA/L, concerning 57.1% of females at the highest concentration (1000 μg BPA/L). A few carp from the same highest treatment also showed intersexuality (27%). Oestradiol-17β (E2) significantly decreased both in 1 and 10 μg BPA/L exposed carp reaching again values not significantly different from control in 1000 μg BPA/L. At this concentration, a significant reduction of testosterone (T) was observed in both males and females. The mean plasma concentration of VTG significantly increased in 1000 μg BPA/L exposed carp, even if a growing number of responsive carp was observed starting from the environmental concentrations (1 and 10 μg BPA/L).
Laryngopharyngeal reflux (LPR) is a complex problem in pediatric population: diagnosis and clinical presentation are still controversial.
Classic white light endoscopy shows some pathognomonic signs ...of LPR in children, such as thickening of pharyngo-laryngeal mucus, the cobblestoning aspect of pharyngeal mucosa, arytenoid edema/hyperemia, nodular thickening/true vocal cord edema, hypertrophy of the posterior commissure, subglottic edema.
The NBI (Narrow Band Imaging) technology, generally used in oncology, allows to study neoangiogenesis and hypervascularization of the mucosa, common aspects in both chronic inflammation and neoplastic transformation. The aim of our study was to evaluate the added value of this technology in identifying the main laryngopharyngeal reflux sign in a pediatric population.
We evaluated at the Otolaryngology Unit of the “Fondazione Policlinico A. Gemelli” hospital and the Airway Surgery Unit of the “Bambino Gesù” Children's Hospital 35 patients aged from 2 months to 16 years divided into two groups in the period between November 2017 and May 2018. Group A included patients with clinical suspicion of LPR after gastroenterologist evaluation and Group B included patients who underwent an endoscopic evaluation for the assessment of recurrent respiratory symptoms such as stridor, recurrent croup, wheezing and persistent cough. We performed an endoscopic evaluation by white light and NBI for each patient, comparing the results of both methods to evaluate signs of pharyngo-laryngeal reflux and to calculate the value of reflux finding score (RFS).
The analysis of the data showed: for Group A an average value of RFS with white light of 11,84 (range 8–17, standard deviation 2,52 ± 0,57) and with NBI of 13,63 (range 10–17, standard deviation 2,13 ± 0,49); for Group B the analysis of the data showed an average value of RFS with white light of 10,06 (range 8–14, standard deviation 2,32 ± 0,58) and with NBI of 12,50 (range 9–18, standard deviation 2,63 ± 0,65). The comparison between the two methods resulted significant.
Furthermore evaluation by NBI allowed to highlight other signs of pharyngo-laryngeal reflux, characteristic of pediatric age and not included in RFS, in particular cobblestone aspect of the hypopharingeal mucosa, phlogosis of the tonsillar crypts and adenoid surface, hyperemia and hypervascularization of subglottic and tracheal mucosa.
Although still preliminary our results represent an interesting starting point for further studies, because they underline the potentiality of NBI endoscopy in LPR evaluation and how this technology could improve the identification of reflux signs.
Neonatal subglottic stenosis still remains a substantial challenge for paediatric ENT surgeons. Herein, we present a case of a single stage laryngotracheal reconstruction for a glottic-subglottic ...stenosis in an 18-week-old, 7.2 kg infant with DiGeorge syndrome. Our surgical approach was compared with those reported in the literature. Paediatric airway surgery should be tailored to individual patients according to age, weight, comorbidities and family collaboration, with the ultimate objective to minimise the invasiveness of the procedure.
Capillary pressure–saturation relationship plays an important role in the description of two-phase flow in porous media. Commonly, this relationship is determined in laboratory on a sample of few ...centimeters and it is then used in numerical modeling of two-phase in domain sizes of hundreds to thousands of meters. The correctness of such approach has been hardly ever questioned. In this study, an upscaled capillary pressure is determined from local pressure and saturation measurements employing a rigorous averaging procedure. Drainage and imbibition experiments were performed in a column of 21 cm long. The experiments were performed as a series of equilibrium steps; each time we changed the boundary pressures incrementally and then waited until an equilibrium distribution of fluids was reached. Phase pressures and saturation inside the column as well as external pressure and average saturation were recorded at each equilibrium step. Various averaging operators were considered:
simple average
,
simple phase-average
,
intrinsic phase-average
, and
centroid-corrected average
. Also, a
potential-based
average operator was introduced as reference curve to establish which operator gives the correct average pressure. Large differences were found for the average non-wetting phase pressure using different operators during primary drainage. However, when both phases were present throughout the domain (e.g. during main drainage) the differences between pressures obtained by various average operators were negligible. In such cases, the centroids of the two phases and the centroid of the averaging domain were close to each other. The comparison between averaged capillary pressure–saturation curves has shown that the
centroid-corrected
averaging operator is the most appropriate operator.
Abstract We report a case of worsening respiratory distress associated with opisthotonus secondary to tracheomalacia, a rather unique pathophysiological phenomenon. A 2-month-old male baby was ...referred to our hospital for respiratory distress syndrome with a noticeable opisthotonus. Examination and investigation confirmed the presence of an aberrant innominate artery compressing the trachea. The infant underwent aortopexy and made a dramatic post-operative recovery. Of special note, the opisthotonus vanished soon after the operation. Opisthotonus is not always related to neurological impairment and may be a warning sign of mediastinal overcrowding in patients with respiratory distress syndrome secondary to vascular compression.
Emerging and re-emerging infectious disease in otorhinolaryngology (ENT) are an area of growing epidemiological and clinical interest. The aim of this section is to comprehensively report on the ...epidemiology of key infectious disease in otorhinolaryngology, reporting on their burden at the national and international level, expanding of the need of promoting and implementing preventive interventions, and the rationale of applying evidence-based, effective and cost- effective diagnostic, curative and preventive approaches. In particular, we focus on i) ENT viral infections (HIV, Epstein-Barr virus, Human Papilloma virus), retrieving the available evidence on their oncogenic potential; ii) typical and atypical mycobacteria infections; iii) non-specific granulomatous lymphadenopathy; iv) emerging paediatric ENT infectious diseases and the prevention of their complications; v) the growing burden of antimicrobial resistance in ENT and the strategies for its control in different clinical settings. We conclude by outlining knowledge gaps and action needed in ENT infectious diseases research and clinical practice and we make references to economic analysis in the field of ENT infectious diseases prevention and care.
Different endpoints have been used to investigate the occurrence of estrogenic risk along the Po River, particularly its middle section. An in vitro assay based on recombinant yeast could not detect ...estrogenic activity in bed sediments of the Italian river or in bile samples of five Cyprinid species, with the only exception being one carp (Cyprinus carpio) captured downstream of the River Lambro, a polluted tributary of the middle River Po. Chemical analyses of fish bile and water samples from the same middle section showed diffuse contamination by moderately low levels of estrogenic chemicals (estrone E₁, 17β-estradiol, estriol E₃, 17α-ethinylestradiol, 4-nonylphenol NP, 4-tert-octylphenol tOP, 4-n-octylphenol, and bisphenol A) but they were of limited help in understanding the risk present in the downstream area where intersex barbel were previously found. In contrast, the analyses of River Lambro waters showed that this tributary is a source to the middle River Po of all eight estrogens investigated. Analyses of bed sediments and macroinvertebrates from the same area consistently showed at least two levels of contamination, with the downstream stretch showing higher concentrations of natural steroids (E₁ and E₃) and xenoestrogens (NP and tOP). Accordingly, new histologic examinations undertaken on young barbel (Barbus sp.) showed intersex gonads only in the individuals captured in the downstream stretch, thereby confirming previous results. Present findings confirm the occurrence of disrupting conditions in the middle River Po and provide the first suggestions of cause-effect relationships.
Barbel (
Barbus plebejus, Cyprinidae) were captured in the Po River, upstream and downstream from the confluence of the Lambro River, a polluted tributary of the major Italian watercourse. The gonads ...of the two groups of barbel have been histologically examined, and only the downstream specimens showed histo-morphological alterations that can be related to the Lambro tributary as a source to the main river of endocrine disrupting chemicals, possibly with estrogenic effects. In fact, 50% of the barbel captured (8 of 16 fish) in the downstream reach showed intersex gonads.
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