Experimental investigation on free surface vortices driven by tangential inlets

Particle Image Velocimetry (PIV) measurements have been carried out in order to analyze the structure of free surface vortices in a promoting geometry with two tangential inlets. Velocity fields associated to the free surface vortex have been obtained at different horizontal planes and Reynolds numbers. Average velocity fields have been calculated and tangential velocity profiles have been compared at different vortex stages and measurement planes. The results show that tangential flow is uniform along the vortex axis and it scales well with the average exit velocity. The tangential velocity profiles, in comparison to the potential behavior, show discrepancies especially at large distances from the vortex axis. Vorticity fields and circulation profiles have been also derived from the measured velocity fields and discussed. The circulation profiles increase along the vortex radius even at large distances from the vortex axis, so that the potential solution is not applicable at all. The comparison of tangential velocity and circulation profiles between promoted and free vortices, the last presented in a previous paper, shows that the tangential motion in a driven vortex is more intense and predominant over the sink effect (radial motion), except very close to the tank bottom, as in a forced configuration (i.e. rotating cylindrical tank)

Influence of Boundary Conditions in Numerical Simulation of Free Surface Vortices

Abstract A numerical evaluation of gas core length in free surface vortices had been performed, applying different approaches. In the past only partial satisfactory agreement with experimental results was obtained because of an excessive simplification of the computational domain. In this work, two-phase CFD simulations (with Volume Of Fluid method) have been performed using a computational domain without any simplification and the evolution of the vortex formation has been analyzed in term of gas core length. Different turbulence models have been tested. A mesh sensitivity analysis has been performed. The new numerical results obtained with the most advanced turbulence model (SST SAS-CC) show an improved agreement with experimental data, with respect to the previous results, confirming the importance of imposing proper boundary conditions to correctly simulate free surface vortices

Investigation on bathtub vortex flow field by Particle Image Velocimetry

An experimental investigation on bathtub vortices has been performed by using Particle Image Velocimetry (PIV). Velocity fields associated to the free surface vortex were obtained at three horizontal planes and four Reynolds numbers, i.e. between 2400 and 11000 (calculated with reference to the exit hole diameter and the mean exit velocity). Due to the unsteady behavior of the low field, the vortex center positions have been identified and the vortex paths were reconstructed for all experiments. Average velocity fields have been calculated by aligning the vortex centers at each frame, in order to derive radial and tangential velocity profiles, to be compared at different Reynolds numbers and measurement planes. The results show that the radial motion assumes a potential behavior when it is near the exit hole, scaling quite well with the average exit velocity (thus with the corresponding Reynolds number). On the other hand, the tangential component is well approximated by the Rankine’s flow potential solution only near the free surface, the tangential velocity peak increment not being linearly proportional to the outlet velocity. Vorticity fields and circulation profiles have been derived from the measured velocity fields and discussed. Turbulence fluctuations statistical analysis gives also evidence of a clear dependence on Reynolds number and distance from the exit hole

A rare case of omental extra-gastrointestinal stromal tumor showing two coexisting mutations on exon 14 of the PDGFRA gene

Gastrointestinal stromal tumors (GISTs) are neoplasms arising from mesenchymal cells localized into the muscularis propria of the gastrointestinal (GI) tract [1]; 5% of GISTs are extra-GISTs (EGISTs), as they differently originate from adipose tissue adjacent to the GI tract (omentum and mesentery) or from the pancreas [2]. So far, both GISTs and EGISTs have been managed indistinctively by combining surgery, histopathological distinctive features, imaging, and molecular analysis. Moreover, despite the contribution of defined genetic backgrounds whose influence is acknowledged in this type of tumor (i.e. Carney’s triad or familiar form of GIST), the pathobiology of both GISTs and EGISTs is not yet fully understood. We describe an interesting case of an extensively diffuse EGIST involving only omentum and mesocolon with multinodular growth and peculiar histological features, and for which a deeper histopathological/ molecular analysis is reported. Case presentation A 74-year-old female with a historical diagnosis of multiple myeloma was referred for anemia, alvus disorders (diarrhea and constipation), weight loss (15 kg in 6 months), and palpable mass of the right flank that had appeared 8 weeks before. On medication for multiple myeloma since 2016 (melphalan combined with prednisone and bortezomib9; carfilzomib/lenalidomide/ desametasone6 until complete remission), she also had type II diabetes, treated with oral medications and open cholecystectomy in the 1980s. Physical examination revealed the presence of a large mobile non-painful mass in the right flank apparently from the right colon, without signs of occlusion or intestinal bleeding. Blood analysis showed: hemoglobin 7.9 g/dL, white blood cells 2.3103/lL, glycemia 191 mg/dL, and a low potassium level of 2.8 mEq/L. We first treated the glycemia by insulin infusion and, second, we investigated the signs of anemia. By lower GI Submitted: 14 May 2020; Revised: 20 July 2020; Accepted: 28 July 202

Acute respiratory virus emergency department admissions in a tertiary care hospital in Central Italy and the relative impact on bed occupancy, January 2017-May 2022

Acute Respiratory Infections (ARIs) have a relevant impact on public health in terms of prevalence and costs associated with the diseases. This concern highlighted the need to adopt accurate surveillance systems to respond to new emergencies and meet the demand for access to care. The objective of our work is to set up, at the Azienda Ospedaliero-Universitaria Pisana (AOUP), an automated syndromic surveillance for ARI

BRAF and NRAS mutations are heterogeneous and not mutually exclusive in nodular melanoma

Inhibitors of RAF inhibit the MAPK pathway that plays an important role in the development and progression of those melanoma carrying the V600E BRAF mutation, but there's a subset of such patients who do not respond to the therapy. Various mechanisms of drug resistance have been proposed which include the clonal heterogeneity of the tumor. We have studied a population of nodular melanoma to investigate the intratumor and intertumor heterogeneity by Laser Capture Microdissection (LCM) analysis. Our results showed that BRAF and NRAS mutations were detected in 47% and 33% of nodular melanoma, respectively, and that there is a discrepancy in mutational pattern of tumoral sample because in the 36% of patients a different mutation, in at least 1 area of the tumor, was found by LCM analysis, giving evidence of the presence of different clonal cells populations. Moreover, we found that mutations in BRAF and NRAS are not mutually exclusive because they were simultaneously present in the same tumor specimens and we observed that when the 2 different mutations were present one is a high-frequency mutation and the other is a low-frequency mutation. This was more evident in lymphonodal metastasis that resulted from wild type to mutational analysis, but showed different mutations following LCM analysis. Therefore, we believed that, when primary tumoral sample results negative to mutational analysis, if it is possible, metastases should be investigated to verify the presence of mutations. Generally, it should be searched for other mutations, in addition to BRAF V600E, so as to better understand the mechanism of drug resistance.This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivitives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/3.0

Genome analysis and gene expression profiling of neuroblastoma and ganglioneuroblastoma reveal differences between neuroblastic and Schwannian stromal cells

Neuroblastic tumours are a group of paediatric cancers with marked morphological heterogeneity. Neuroblastoma (Schwannian stroma-poor) (NB-SP) is composed of undifferentiated neuroblasts. Ganglioneuroblastoma intermixed (Schwannian stroma-rich) (GNBi-SR) is predominantly composed of Schwannian stromal (SS) and neuroblastic (Nb) cells. There are contrasting reports suggesting that SS cells are non-neoplastic. In the present study, laser capture microdissection (LCM) was employed to isolate SS and Nb cells. Chromosome 1p36 deletion and MYCN gene amplification were found to be associated in two out of seven NB-SPs, whereas no abnormalities were observed in five GNBi-SRs. In some cases, loss of heterozygosity (LOH) at 1p36 loci was detected in Nb cells but not in the bulk tumour by LCM; furthermore, LOH was also identified in both SS and tumour tissue of a GNBi-SR. DNA gain and loss studied by comparative genomic hybridization were observed at several chromosome regions in NB-SP but in few regions of GNBi-SR. Finally, gene expression profiles studied using an oligo-microarray technique displayed two distinct signatures: in the first, 32 genes were expressed in NB-SP and in the second, 14 genes were expressed in GNBi-SR. The results show that NB-SP is composed of different morphologically indistinguishable malignant cell clones harbouring cryptic mutations that are detectable only after LCM. The degree of DNA imbalance is higher in NB-SP than in GNBi-SR. However, when the analysis of chromosome 1p36 is performed at the level of microdissection, LOH is also observed in SS cells. These data provide supportive evidence that SS cells have a less aggressive phenotype and play a role in tumour maturation. Copyright © 2005 Pathological Society of Great Britain and Ireland

The evolving landscape in the management of gastric metastases from melanoma: a case series

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PAX3 Expression in Normal Skin Melanocytes and Melanocytic Lesions (Naevi and Melanomas)

Background Cutaneous Malignant Melanoma is an aggressive form of skin cancer, arising in cutaneous melanocytes. The transcription factor PAX3 regulates melanocyte specification from neural crest cells during development but expression in differentiated melanocytes is uncertain. By contrast it is frequently found in melanomas and naevi and is a marker for melanoma staging and detection. In this study we analysed the expression of PAX3 across the spectrum of melanocytic cells, from normal melanocytes to cells of benign and malignant lesions to better assess its function in these various tissues. Pax3 and PAX3 (italicized) refer to the mouse and human gene, respectively; whereas Pax3 and PAX3 (non-italicized) refer to the corresponding mouse and human protein. Methodology and Principal Findings PAX3 expression was analysed by immunohistochemistry and qRT-PCR. Immunofluorescence was used for co-expression with differentiation, migration and survival markers. As expected PAX3 expression was observed in naevi and melanoma cells. It was also found in melanocytes of normal skin where it co-expressed with melanocyte markers, MITF and MLANA. Co-expression with its downstream target, antiapoptotic factor BCL2L1 confirms PAX3 as a cell survival regulator. PAX3 was also co-expressed with melanoma cell migration marker MCAM in dermal naevi and melanoma cell nests, but this downstream target of PAX3 was not present in normal epidermal melanocytes, suggesting differential roles for PAX3 in normal epidermal melanocytes and melanoma cells. Most interestingly, a proportion of PAX3-positive epidermal melanocytes in normal skin show HES1 and Ki67 co-expression, indicating their less differentiated proliferative phenotype. Conclusions and Significance Our results suggest that a previously identified role for PAX3, that of regulator of an undifferentiated plastic state, may operate in melanocytes of normal skin. This role, possibly required for cellular response to environmental stimuli, may contribute to formation and development of melanocytic lesions in which PAX3 expression is prominent

CALYPSO 2019 Cruise Report: field campaign in the Mediterranean

This cruise aimed to identify transport pathways from the surface into the interior ocean during the late winter in the Alborán sea between the Strait of Gibraltar (5°40’W) and the prime meridian. Theory and previous observations indicated that these pathways likely originated at strong fronts, such as the one that separates salty Mediterranean water and the fresher water in owing from the Atlantic. Our goal was to map such pathways and quantify their transport. Since the outcropping isopycnals at the front extend to the deepest depths during the late winter, we planned the cruise at the end of the Spring, prior to the onset of thermal stratification of the surface mixed layer.Funding was provided by the Office of Naval Research under Contract No. N000141613130