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Aluminum to titanium laser welding-brazing in V-shaped grooveI
2017
International audience; Laser assisted joining of AA5754 aluminum alloy to T40 titanium with use of Al-Si filler wires was carried out. Continuous Yb:YAG laser beam was shaped into double spot tandem and defocalized to cover larger interaction zone in V shaped groove. Experimental design method was applied to study the influence of operational parameters on the tensile properties of the joints. Microstructure examination and fractography study were carried out to understand the relation between local phase content and fracture mode.Within defined window of operational parameters, statistically important factors that influenced the strength of T40 to AA5754 joints in V groove configuration w…
On the complete interface development of Al/Cu magnetic pulse welding via experimental characterizations and multiphysics numerical simulations
2021
Abstract A complex Al/Cu magnetic pulse welding interface is systematically investigated using experimental characterizations and numerical simulations. A Coupled electromagnetic-mechanical simulation is proposed to compute the impact velocity and impact angle along the entire interface. This model allows to further understand the formation mechanism of various interface characteristics during MPW. The results revealed that the impact velocity gradually decreases in conjunction with the gradual increase of the impact angle. These simulations elucidate the experimentally observed successive interface morphologies, i.e., the unwelded zone, vortex zone, intermediate (IM) layers and wavy interf…
The protein and microRNA cargo of extracellular vesicles from parasitic helminths – current status and research priorities
2020
Helminth parasites have a remarkable ability to persist within their mammalian hosts, which is largely due to their secretion of molecules with immunomodulatory properties. Although the soluble components of helminth secretions have been extensively studied, the discovery that helminths release extracellular vesicles (EVs) has added further complexity to the host-parasite interaction. Whilst several studies have begun to characterise the molecules carried by helminth EVs, work aimed at investigating their biological functions has been hindered by a lack of helminth-specific EV markers. To begin to address this, we summarised helminth EV literature to date. With a focus on the protein and mi…
Diversity, evolution, and function of myriapod hemocyanins.
2018
Background Hemocyanin transports O2 in the hemolymph of many arthropod species. Such respiratory proteins have long been considered unnecessary in Myriapoda. As a result, the presence of hemocyanin in Myriapoda has long been overlooked. We analyzed transcriptome and genome sequences from all major myriapod taxa – Chilopoda, Diplopoda, Symphyla, and Pauropoda – with the aim of identifying hemocyanin-like proteins. Results We investigated the genomes and transcriptomes of 56 myriapod species and identified 46 novel full-length hemocyanin subunit sequences in 20 species of Chilopoda, Diplopoda, and Symphyla, but not Pauropoda. We found in Cleidogona sp. (Diplopoda, Chordeumatida) a hemocyanin-…
Identification and Characterization of a Single High-Affinity Fatty Acid Binding Site in Human Serum Albumin.
2017
A single high-affinity fatty acid binding site in the important human transport protein serum albumin (HSA) is identified and characterized using an NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl)-C12 fatty acid. This ligand exhibits a 1:1 binding stoichiometry in its HSA complex with high site-specificity. The complex dissociation constant is determined by titration experiments as well as radioactive equilibrium dialysis. Competition experiments with the known HSA-binding drugs warfarin and ibuprofen confirm the new binding site to be different from Sudlow-sites I and II. These binding studies are extended to other albumin binders and fatty acid derivatives. Furthermore an X-ray crystal structure …
Stability of a Split Streptomycin Binding Aptamer
2016
Here we investigated the stability of an aptamer, which is formed by two RNA strands and binds the antibiotic streptomycin. Molecular dynamics simulations in aqueous solution confirmed the geometry and the pattern of hydrogen bond interactions that was derived from the crystal structure (1NTB). The result of umbrella sampling simulations indicated a favored streptomycin binding with a free energy of ΔGbind° = −101.7 kJ mol–1. Experimentally, the increase in oligonucleotide stability upon binding of streptomycin was probed by single-molecule force spectroscopy. Rate dependent force spectroscopy measurements revealed a decrease in the natural off-rate (koff-COMPLEX = 0.22 ± 0.16 s–1) for the …
Targeting distinct myeloid cell populations in vivo using polymers, liposomes and microbubbles
2016
Identifying intended or accidental cellular targets for drug delivery systems is highly relevant for evaluating therapeutic and toxic effects. However, limited knowledge exists on the distribution of nano- and micrometer-sized carrier systems at the cellular level in different organs. We hypothesized that clinically relevant carrier materials, differing in composition and size, are able to target distinct myeloid cell subsets that control inflammatory processes, such as macrophages, neutrophils, monocytes and dendritic cells. Therefore, we analyzed the biodistribution and in vivo cellular uptake of intravenously injected poly(N-(2-hydroxypropyl) methacrylamide) polymers, PEGylated liposomes…
Efficacy and Resistance Management Potential of a Modified Vip3C Protein for Control of Spodoptera frugiperda in Maize
2018
AbstractA modified Vip3C protein has been developed that has a spectrum of activity that has the potential to be commercially useful for pest control, and shows good efficacy against Spodoptera frugiperda in insect bioassays and field trials. For the first time Vip3A and Vip3C proteins have been compared to Cry1 and Cry2 proteins in a complete set of experiments from insect bioassays to competition binding assays to field trials, and the results of these complementary experiments are in agreement with each other. Binding assays with radiolabelled toxins and brush border membrane vesicles from S. frugiperda and Helicoverpa armigera show that the modified Vip3C protein shares binding sites wi…
Microenvironments to study migration and somal translocation in cortical neurons
2018
Migrating post-mitotic neurons of the developing cerebral cortex undergo terminal somal translocation (ST) when they reach their final destination in the cortical plate. This process is crucial for proper cortical layering and its perturbation can lead to brain dysfunction. Here we present a reductionist biomaterials platform that faithfully supports and controls the distinct phases of terminal ST in vitro. We developed microenvironments with different adhesive molecules to support neuronal attachment, neurite extension, and migration in distinct manners. Efficient ST occurred when the leading process of migratory neurons crossed from low-to high-adhesive areas on a substrate, promoting spr…
A receptor-antibody hybrid hampering MET-driven metastatic spread
2021
AbstractBackgroundThe receptor encoded by the MET oncogene and its ligand Hepatocyte Growth Factor (HGF) are at the core of the invasive-metastatic behavior. In a number of instances genetic alterations result in ligand-independent onset of malignancy (METaddiction). More frequently, ligand stimulation of wild-type MET contributes to progression toward metastasis (METexpedience). Thus, while MET inhibitors alone are effective in the first case, combination therapy with ligand inhibitors is required in the second condition.MethodsIn this paper, we generated hybrid molecules gathering HGF and MET inhibitory properties. This has been achieved by ‘head-to-tail’ or ‘tail-to-head’ fusion of a sin…