Search Results (9)

Unsteady turbulent flows are present in most engineering applications of practical relevance. In aeronautics, these applications span the speed range from subsonic to hypersonic flows. Thus, it is important that our mathematical models and numerical techniques can represent the various flow regimes in a seamless way. The latter is the main motivation of the current paper, which extends the PANS turbulence model to compressible and high-speed flows. The new model, called BPANS-CC, blends the (k,ε) and (k,ω) versions of PANS. In addition, a compressibility correction is added to the new model to expand its simulation range into the compressible high-speed flow regime. The new model was implemented in various CFD software, both academic and commercial. Several well-known benchmark problems were used to test the new model, and the results are in good agreement with experimental data. Full article

Unmanned Aerial Vehicle (UAV) vehicle-tracking technology has extensive potential for application in various fields. In the actual tracking process, the relative movement of the UAV and vehicles will bring large target-scale variations (i.e., size and aspect ratio change), which leads to missed detection and ID switching. Traditional tracking methods usually use multi-scale estimation to adaptively update the target scale for variable-scale detection and tracking. However, this approach requires selecting multiple scaling factors and generating a large number of bounding boxes, which results in high computational costs and affects real-time performance. To tackle the above issue, we propose a novel multi-target tracking method based on the BoT-SORT framework. Firstly, we propose an FB-YOLOv8 framework to solve the missed detection problem. This framework incorporates a Feature Alignment Aggregation Module (FAAM) and a Bidirectional Path Aggregation Network (BPAN) to enhance the multi-scale feature fusion. Secondly, we propose a multi-scale feature-fusion network (MSFF-OSNet) to extract appearance features, which solves the ID switching problem. This framework integrates the Feature Pyramid Network (FPN) and Convolutional Block Attention Module (CBAM) into OSNet to capture multilevel pixel dependencies and combine low-level and high-level features. By effectively integrating the FB-YOLOv8 and MSFF-OSNet modules into the tracking pipeline, the accuracy and stability of tracking are improved. Experiments on the UAVDT dataset achieved 46.1% MOTA and 65.3% IDF1, which outperforms current state-of-the-art trackers. Furthermore, experiments conducted on sequences with scale variations have substantiated the improved tracking stability of our proposed method under scale-changing conditions. Full article

Neurodegeneration with brain iron accumulation (NBIA) involves a group of rare neurogenetic disorders often linked with iron overload in the basal nuclei of the brain presenting with spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration. Among NBIA subtypes, beta-propeller-protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45 (WD repeat domain 45). Previously, we demonstrated that WDR45 mutations in BPAN cellular models impaired autophagy, iron metabolism, and cell bioenergetics. In addition, antioxidant supplementation partially improved cell physiopathology; however, autophagy and cell bioenergetics remained affected. In this work, we explored the possibility of expressing the normal WDR45 allele present in the inactive chromosome X (Xi) of BPAN cells through treatment with epigenetic modulators. The aim of this study was to demonstrate whether biotin, an epigenetic nutrient, was able to restore the expression levels of WDR45 by a mechanism involving Xi reactivation and, consequently, correct BPAN defects. Our study demonstrated that biotin supplementation increases histone biotinylation and allows for the transcription of the WDR45 allele in Xi. Consequently, all physiopathological alterations in BPAN cells were notably corrected. The reactivation of Xi by epigenetic modulators can be a promising approach for the treatment of BPAN and other X-linked diseases. Full article

In-situ polymerization is an effective method for integrating co-catalysts homogeneously into the polymer matrix. Polyacrylonitrile (PAN)-derived highly graphitized carbon is a state-of-the-art material with diverse applications, including materials for energy storage devices, electrocatalysis, sensing, adsorption, and making structural composites of various technologies. Such highly graphitized materials can be effectively obtained through in-situ polymerization. The addition of external catalysts during in-situ polymerization not only enhances the polymerization rate but also facilitates the degree of graphitization and quality of graphitic carbon upon graphitization at moderate temperatures. In this study, we apply an in-situ polymerization technique to integrate aluminum triflate (Al(OTf)₃) and zirconocene dichloride (C₅H₅)₂ZrCl₂ co-catalyst into a boronated polyacrylonitrile (B-PAN) matrix. The in-situ polymerization ensures the uniform distribution of the co-catalyst without aggregation, facilitating the formation of a well-ordered graphitic structure at a moderated temperature. Boronated polyacrylonitrile (B-PAN) solutions, with and without co-catalyst (Al(OTf)₃, (C₅H₅)₂ZrCl₂ or both) were prepared through polymerization process, dried in an oven, and then subjected to graphitization at 1250 °C with a heating rate of 1 °C min⁻¹ for 1 h under an N₂ atmosphere. The resulting graphitic carbon was characterized to determine the impact of co-catalyst on the degree of graphitization. This study provides valuable insights into synthesizing high-quality graphitic carbon materials, offering promising pathways for their scalable production through the strategic use of in-situ polymerization and co-catalysis. These materials have potential applications in various fields, including environmental technologies, energy storage, and conversion, offering a pathway to design facile and economical graphitic carbon materials. Full article

Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain. Among NBIA subtypes, β-propeller protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45. The aim of this study was to demonstrate the autophagic defects and secondary pathological consequences in cellular models derived from two patients harboring WDR45 mutations. Both protein and mRNA expression levels of WDR45 were decreased in patient-derived fibroblasts. In addition, the increase of LC3B upon treatments with autophagy inducers or inhibitors was lower in mutant cells compared to control cells, suggesting decreased autophagosome formation and impaired autophagic flux. A transmission electron microscopy (TEM) analysis showed mitochondrial vacuolization associated with the accumulation of lipofuscin-like aggregates containing undegraded material. Autophagy dysregulation was also associated with iron accumulation and lipid peroxidation. In addition, mutant fibroblasts showed altered mitochondrial bioenergetics. Antioxidants such as pantothenate, vitamin E and α-lipoic prevented lipid peroxidation and iron accumulation. However, antioxidants were not able to correct the expression levels of WDR45, neither the autophagy defect nor cell bioenergetics. Our study demonstrated that WDR45 mutations in BPAN cellular models impaired autophagy, iron metabolism and cell bioenergetics. Antioxidants partially improved cell physiopathology; however, autophagy and cell bioenergetics remained affected. Full article

Nowadays, fluorophores with a tetraphenylethylene (TPE) core are considered interesting due to the aggregation-induced emission (AIE) behavior that enables their effective use in polymer films. We propose a novel TPE fluorophore (TPE-BPAN) bearing two dimethylamino push and a 4-biphenylacetonitrile pull moieties with the typical AIE characteristics in solution and in the solid state, as rationalized by DFT calculations. Five different host polymer matrices with different polarity have been selected: two homopolymers of poly(methylmethacrylate) (PMMA) and poly(cyclohexyl methacrylate) (PCHMA) and three copolymers at different compositions (P(MMA-co-CHMA) 75:25, 50:50, and 25:75 mol%). The less polar comonomer of CHMA appeared to enhance TPE-BPAN emission with the highest quantum yield (QY) of about 40% measured in P(MMA-co-CHMA) 75:25. Further reduction in polymer polarity lowered QY and decreased the film stability and adhesion to the glass surface. LSC performances were not significantly affected by the matrix’s polarity and resulted in around one-third of the state-of-the-art due to the reduced QY of TPE-BPAN. The theoretical investigation based on density functional theory (DFT) calculations clarified the origin of the observed AIE and the role played by the environment in modulating the photophysical behavior. Full article

Characterization of unsteady loads is critical for the development of control systems for next-generation air vehicles. Both Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) methods are prohibitively expensive, and existing Reynolds-Averaged Navier-Stokes (RANS) approaches have been shown to be inadequate in predicting both mean and unsteady loads. In recent years, scale-resolving methods, such as Partially Averaged Navier-Stokes (PANS) and Detached Eddy Simulation (DES), have been gaining acceptance and filling the gap between RANS and LES. In this study, we focus on a new variant of the PANS method, namely blended PANS or BPANS, which was shown to perform well in the incompressible regime for both wall-bounded and free shear flows. In this paper, we extend BPANS to compressible supersonic flows by adding a compressibility correction, leading to a new model called BPANS CC. The new model is tested using a well-known supersonic mixing layer case, and the results show good agreement with experimental data. The model is then used on a complex supersonic retropropulsion case and the results are in good agreement with experimental data. Full article

Beta-propeller protein-associated neurodegeneration (BPAN) is a subtype of neurodegeneration with brain iron accumulation (NBIA) caused by loss-of-function variants in WDR45. The underlying mechanism of iron accumulation in WDR45 deficiency remains elusive. We established a primary skin fibroblast culture of a new BPAN patient with a missense variant p.(Asn61Lys) in WDR45 (NM_007075.3: c.183C>A). The female patient has generalized dystonia, anarthria, parkinsonism, spasticity, stereotypies, and a distinctive cranial MRI with generalized brain atrophy, predominantly of the cerebellum. For the functional characterization of this variant and to provide a molecular link of WDR45 and iron accumulation, we looked for disease- and variant-related changes in the patient’s fibroblasts by qPCR, immunoblotting and immunofluorescence comparing to three controls and a previously reported WDR45 patient. We demonstrated molecular changes in mutant cells comprising an impaired mitochondrial network, decreased levels of lysosomal proteins and enzymes, and altered autophagy, confirming the pathogenicity of the variant. Compared to increased levels of the ferritinophagy marker Nuclear Coactivator 4 (NCOA4) in control cells upon iron treatment, patients’ cells revealed unchanged NCOA4 protein levels, indicating disturbed ferritinophagy. Additionally, we observed abnormal protein levels of markers of the iron-dependent cell death ferroptosis in patients’ cells. Altogether, our data suggests that WDR45 deficiency affects ferritinophagy and ferroptosis, consequentially disturbing iron recycling. Full article

104 MHz-surface acoustic wave sensors have been functionalized with three new anthracenederivatives for the detection of mercury and copper heavy ions: 2,2-bis(4 anthracenylme,thoxy-1,1′-biphenyl(BP-AN), 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl}methyl)]methyl] anthracene (TDP-AN) and 4-(9-anthrylmethoxy) benzyl [4-(9-anthrylmethoxy) phenyl] sulfone (BPS-AN). Gravimetric results indicate that, compared to TDP-AN and BPS-AN, BP-AN based chemsensor has the highest affinitytowards the two investigated ions.The corresponding sensitivities were of order of 3.67 × 10⁸ °/M and 2.24 × 10⁸ °/M for Hg²⁺ and Cu²⁺ respectively. The limit of detection of the BP-AN-SAW chemsensor, of order of 1 pM, is one of the lowest values ever reported in the literature. Experimental results were supported by quantum chemical calculations, based on the density functional theory. Full article