This paper studies the permeability values of air filter media obtained by 3‐D simulations using the GeoDict® code. 3‐D fibrous structures with different specific characteristics that can be ...encountered in air filtration (0.03 ≤ solid volume fraction α ≤ 0.25, monodisperse fibres 1 μm ≤ df ≤8 μm, or polydisperse fibres) were generated. For monodisperse fibres, the permeability values obtained were compared with various correlations identified in the literature. After confirming that Davies' or Jackson and James' relations allowed a good estimate of the permeability, it is shown that the modified Happel's correlation provides a better prediction. In the case of normal (standard deviation: σ ≤ 1.5) or lognormal fibre size distribution (geometric standard deviation: σG ≤ 2), this modified Happel's correlation, in which the fibre diameter is replaced by an equivalent fibre diameter, leads to a relative deviation of less than ±8% and ±4% for lognormal and normal fibre distributions, respectively. The comparison with experimental permeability values obtained on real media provides quite encouraging results.
The success of artificial intelligence and machine learning is an incentive to develop new algorithms to increase the rapidity and reliability of medical diagnosis. Here we compared different ...strategies aimed at processing microscope images used to detect anti-neutrophil cytoplasmic antibodies, an important vasculitis marker: (i) basic classifier methods (logistic regression, k-nearest neighbors and decision tree) were used to process custom-made indices derived from immunofluorescence images yielded by 137 sera. (ii) These methods were combined with dimensional reduction to analyze 1733 individual cell images. (iii) More complex models based on neural networks were used to analyze the same dataset. The efficiency of discriminating between positive and negative samples and different fluorescence patterns was quantified with Rand-type accuracy index, kappa index and ROC curve. It is concluded that basic models trained on a limited dataset allowed for positive/negative discrimination with an efficiency comparable to that obtained by conventional analysis performed by humans (0.84 kappa score). More extensive datasets and more sophisticated models may be required for efficient discrimination between fluorescence patterns generated by different auto-antibody species.
The present article outlines the development of a semi‐analytical model devoted to predict the pressure drop induced by clean pleated high‐efficiency particulate air (HEPA) filters. Both experimental ...measurements and numerical simulations are used to characterize the velocity field in the pleat channel. On this basis, a semi‐analytical model is derived to determine the gas flow within the pleat channel. This analytical formulation is used to predict the air pressure evolution according to filtration velocity in the pleat. This model is then validated on the basis of comparisons with measurements found in the scientific literature for different kinds of HEPA filters with different pleat geometries. This model is easy to use, fast to run compared to standard computational fluid dynamics (CFD) approaches, and is in good agreement with the experimental results.
High efficiency particulate air (HEPA) pleated filters are used to ensure the containment of airborne contamination within nuclear facilities. These filters are often the last barrier before a ...potential release of radioactive substances into the environment. The present article focuses on the characterization of air velocity fields within mini‐pleats HEPA filters at the elementary pleat scale. Numerical simulations of the velocity fields in a pleat using two different codes, ANSYS CFX and GeoDict, based on two different simulation strategies have been performed. Computed velocity profiles within the pleat have then been compared to measurements performed using an experimental setup based on a μ‐PIV measurement technique. Results show that both codes are able to reproduce the measured profiles with a satisfying accuracy. However, GeoDict requires a much finer meshing than ANSYS CFX because the voxel size is constant for the whole domain. Simulation and experimental results confirm a self‐similarity profile along the pleat assessed as a hypothesis by other authors working on this topic.
Cardiac fibrosis constitutes irreversible necrosis of the heart muscle as a consequence of different acute (myocardial infarction) or chronic (diabetes, hypertension, …) diseases but also due to ...genetic alterations or aging. Currently, there is no curative treatment that is able to prevent or attenuate this phenomenon that leads to progressive cardiac dysfunction and life-threatening outcomes. This review summarizes the different targets identified and the new strategies proposed to fight cardiac fibrosis. Future directions, including the use of exosomes or nanoparticles, will also be discussed.
•To date, no biological markers have been proposed to predict post-coronavirus disease 2019 (COVID-19) syndrome (PCS).•Immunoglobulin G (IgG) anticardiolipin autoantibodies (aCL) are associated with ...the severity of COVID-19.•This article reports a case of persistent IgG aCL positivity in a patient with PCS.•Persistence of aCL positivity could be a biological predictor of PCS.
Persistence of various symptoms in patients who have recovered from coronavirus disease 2019 (COVID-19) was recently defined as ‘long COVID’ or ‘post-COVID syndrome’ (PCS). This article reports a case of a 58-year-old woman who, although recovering from COVID-19, had novel and persistent symptoms including neurological complications that could not be explained by any cause other than PCS. In addition to a low inflammatory response, persistence of immunoglobulin G anticardiolipin autoantibody positivity and eosinopenia were found 1 year after acute COVID-19 infection, both of which have been defined previously as independent factors associated with the severity of COVID-19. The pathophysiological mechanism of PCS is unknown, but the possibility of persistence of the virus, especially in the nervous system, could be suggested with a post-infectious inflammatory or autoimmune reaction.
Abstract
Whereas the detection of antiphospholipid autoantibodies (aPL) in COVID-19 is of increasing interest, their role is still unclear. We analyzed a large aPL panel in 157 patients with COVID-19 ...according to the disease severity. We also investigated a potential association between aPL and extracellular DNA (exDNA, n = 85) or circulating markers of neutrophil extracellular traps (NET) such as citrullinated histones H3 (CitH3, n = 49). A total of 157 sera of patients infected by SARS-CoV-2 were collected. A large aPL panel including lupus anticoagulant, anti-cardiolipin and anti-beta-2 glycoprotein I (IgG, IgM and IgA), anti-phosphatidylethanolamine IgA, anti-prothrombin (IgG and IgM) was retrospectively analyzed according to the disease severity. We found a total aPL prevalence of 54.8% with almost half of the cases having aCL IgG. Within an extended panel of aPL, only aCL IgG were associated with COVID-19 severity. Additionally, severe patients displayed higher CitH3 levels than mild patients. Interestingly, we highlighted a significant association between the levels of aCL IgG and exDNA only in aCL positive patients with severe disease. In conclusion, we showed a significant link between aPL, namely aCL IgG, and circulating exDNA in patients with severe form of COVID-19, that could exacerbate the thrombo-inflammatory state related to disease severity.
Anti-Jo-1 autoantibodies represent essential markers in the diagnosis of antisynthetase syndrome (ASS). In this retrospective study, we aimed to investigate whether their concentrations and ...fluctuations could both respectively reflect the severity and evolution of ASS.
Between 2015 and 2020, clinical and biological features of ASS patients with at least one positive measure of anti-Jo-1 autoantibody were collected. At each serum sampling, we assessed myositis activity by using the Myositis Intention to Treat Activities Index (MITAX) and compared anti-Jo-1 concentrations with ASS severity, anti-Jo-1 concentrations between patients with and without active disease, and changes in anti-Jo-1 concentrations with disease activity.
Forty-eight patients with ASS had at least one positive determination of anti-Jo-1 concentration. Among them, twenty-nine patients had at least two determinations of anti-Jo-1 autoantibody in their follow-up. We showed that these autoantibody concentrations were significantly correlated with MITAX (r = 0.4, p = 0.03) and creatine kinase concentration (r = 0.34, p = 0.002) and that they were significantly higher in patients with active disease than in those with inactive disease (91.7 IU/L vs 44.4 IU/L, p = 0.016). During follow-up, we found a significant correlation between fluctuations of anti-Jo-1 autoantibody concentrations and MITAX score (r = 0.7, p < 0.0001).
Our results suggest that anti-Jo-1 autoantibody concentration could be a predictive marker of the severity and evolution of ASS and show that their quantification could represent a precious tool for disease monitoring and for improving the therapeutic management of ASS patients.
Triple Negative Breast Cancers (TNBC) are the most aggressive breast cancers and lead to poor prognoses. This is due to a high resistance to therapies, mainly because of the presence of Cancer Stem ...Cells (CSCs). Plasticity, a feature of CSCs, is acquired through the Epithelial to Mesenchymal Transition (EMT), a process that has been recently shown to be regulated by a key molecule, CD146. Of interest, CD146 is over-expressed in TNBC.
The MDA-MB-231 TNBC cell line was used as a model to study the role of CD146 and its secreted soluble form (sCD146) in the development and dissemination of TNBC using in vitro and in vivo studies.
High expression of CD146 in a majority of MDA-MB-231 cells leads to an increased secretion of sCD146 that up-regulates the expression of EMT and CSC markers on the cells. These effects can be blocked with a specific anti-sCD146 antibody, M2J-1 mAb. M2J-1 mAb was able to reduce tumour development and dissemination in a model of cells xenografted in nude mice and an experimental model of metastasis, respectively, in part through its effects on CSC.
We propose that M2J-1 mAb could be used as an additional therapeutic approach to fight TNBC.
CD146 is an adhesion molecule expressed by both melanoma and endothelial cells and thus is well positioned to control melanoma extravasation. Nevertheless, during melanoma metastasis, the involvement ...of CD146 expressed within tumor microenvironment has never been analyzed. To investigate whether host CD146 mediates the extravasation of melanoma cells across the endothelium, we generated CD146 KO mice. We demonstrated that host CD146 did not affect melanoma growth or tumor angiogenesis but promoted hematogenous melanoma metastasis to the lung. Accordingly, the survival of CD146‐deficient mice was markedly prolonged during melanoma metastasis. Interestingly, vascular endothelial growth factor‐induced vascular permeability was significantly decreased in CD146 KO mice. We also provided evidence that VEGF‐induced transendothelial migration of melanoma cells was significantly reduced across CD146 KO lung microvascular endothelial cells (LMEC). CD146 deficiency decreased the expression of VEGFR‐2/Ve‐cadherin and altered focal adhesion kinase (FAK) activation in response to VEGF. In addition, inhibition of FAK phosphorylation reduced transmigration of B16 melanoma cells across WT LMEC at the same level that across CD146 KO LMEC. Altogether, we propose a novel mechanism involving the VEGF/CD146/FAK/Ve‐cadherin network in melanoma extravasation across the vessel barrier that identifies CD146‐targeted therapy as a potential strategy for the treatment of melanoma metastasis.
What's new?
To win the fight against metastatic melanoma—one of the most drug‐resistant cancers—novel therapeutic targets must be identified. A promising candidate is melanoma cell adhesion molecule (MCAM), or CD146, which is present at both endothelial junctions and tumor‐endothelial contact sites, making it well‐positioned to modulate melanoma extravasation. In the present study, CD146‐deficient mice are shown to experience prolonged survival during melanoma metastasis. Evaluation of signaling molecules downstream of CD146 suggests that the VEGF/CD146/FAK/Ve‐cadherin network plays a key role in mediating the hematogenous spread of melanoma to the lungs.
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