The pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection involves dysregulations of iron metabolism, and although the mechanism of this pathology is not yet fully ...understood, correction of iron metabolism pathways seems a promising pharmacological target. The previously observed effect of inhibiting SARS-CoV-2 infection by ferristatin II, an inducer of transferrin receptor 1 (TfR1) degradation, prompted the study of competition between Spike protein and TfR1 ligands, especially lactoferrin (Lf) and transferrin (Tf). We hypothesized molecular mimicry of Spike protein as cross-reactivity of Spike-specific antibodies with Tf and Lf. Thus, strong positive correlations (R
2
> 0.95) were found between the level of Spike-specific IgG antibodies present in serum samples of COVID-19-recovered and Sputnik V-vaccinated individuals and their Tf-binding activity assayed with peroxidase-labeled anti-Tf. In addition, we observed cross-reactivity of Lf-specific murine monoclonal antibody (mAb) towards the SARS-CoV-2 Spike protein. On the other hand, the interaction of mAbs produced to the receptor-binding domain (RBD) of the Spike protein with recombinant RBD protein was disrupted by Tf, Lf, soluble TfR1, anti-TfR1 aptamer, as well as by peptides RGD and GHAIYPRH. Furthermore, direct interaction of RBD protein with Lf, but not Tf, was observed, with affinity of binding estimated by K
D
to be 23 nM and 16 nM for apo-Lf and holo-Lf, respectively. Treatment of Vero E6 cells with apo-Lf and holo-Lf (1–4 mg/mL) significantly inhibited SARS-CoV-2 replication of both Wuhan and Delta lineages. Protective effects of Lf on different arms of SARS-CoV-2-induced pathogenesis and possible consequences of cross-reactivity of Spike-specific antibodies are discussed.
By using a rotating disk electrode, it is shown for the first time that the network structures formed by long ultrathin (diameter ~4 nm) platinum nanowires deposited onto the surface of a glassy ...carbon electrode demonstrate the high specific catalytic activity in the oxygen reduction reaction.
The kinetic regularities of thermal destruction of polycarbonate films containing Pt, Au, Ag, and Ni nanoparticles were studied. Scanning and transmission electron microscopy, as well as surface ...plasmon resonance absorption spectra, were used to determine the sizes and shapes of metal nanoparticles in composite films. Nanocomposites were obtained by various methods: by reduction of a precursor in a polycarbonate solution followed by evaporation of the solvent; by deposition on a polymer film surface of nanoparticles formed as a result of diode sputtering of metal in argon plasma or laser ablation in superfluid helium. The rate of thermal decomposition of polycarbonate nanocomposites exceeded the rate of decomposition of the starting polymer. The highest catalytic ability was exhibited by Pt, Au, and Ni nanoparticles in the form of nanowires with diameters of 2–6 nm.
A version of k-ra SST turbulence model adjusted for flow around airfoils at high Reynolds numbers is presented. The modified version decreases eddy viscosity and significantly improves the accuracy ...of prediction of aerodynamic characteristics in a wide range of angles of attack. However, considered reduction of eddy viscosity destroys calibration of the model, which leads to decreasing accuracy of skin-friction coefficient prediction even for relatively simple wall-bounded turbulent flows. Therefore, the area of applicability of the suggested modification is limited to flows around airfoils.
Laser ablation in superfluid helium has been used to synthesize nanowires with a diameter of less than 10 nm from tin and an indium–tin alloy (In
90
Sn
10
). The morphology, structure, and ...possibility of nanowire oxidation by the action of a focused electron beam have been studied using transmission electron microscopy. It has been shown that tin nanowires undergo only structural changes, transforming from an amorphous to a polycrystalline state. The In
90
Sn
10
nanowires have been oxidized by interacting with residual oxygen in the electron microscope chamber. Taking into account the absence of tin oxidation during electron beam irradiation, the composition of the resulting single-crystalline oxide can be expressed by the formula (In
90
Sn
10
)
2
O
3
.
A tungsten target has been exposed to pulsed laser ablation in vacuum, gaseous helium, and superfluid (liquid) helium, and ablation products have been studied by means of pyrometric measurements. It ...has been shown that quantitative measurement data for thermal emission characteristics shed light on nanostructure condensation mechanisms in these media. From these data, the cross sections of emitting particles have been calculated. It has been found that submicrometer particles emit mostly in vacuum, whereas emission from nanoparticles has been observed in superfluid helium. The obtained data are substantiated by electron microscopic data.
This paper presents the results of extensive testing of four recently proposed algebraic laminar-turbulent transition (LTT) models, which are significantly more computationally effective than ...differential models, while being potentially equally accurate. The models chosen for evaluation, namely, SST KD, SST kγ, SST alg-γ, and SA BCM, are implemented in the in-house code NTS and verified by comparing the obtained results with those published by the models’ authors. The experimental database used for the evaluation of the models includes transitional boundary layers at different free-flow turbulence intensities with and without the pressure gradient, four airfoil flows with different LTT scenarios, and a tandem of two airfoils. It is found that at low levels of turbulence, the results of the SA BCM and SST kγ models may depend on the initial approximation, which does not allow them to be recommended for engineering applications. The best results, comparable in accuracy to those of differential models, are obtained using the SST alg-γ model.
The copper-doped gold nanowires (4 nm in diameter) were produced by the novel technique based of laser ablation of Au–Cu alloy inside superfluid helium. The principle of the method is using the ...quantized vortices as the 1D template for the condensation of the ablation products into thin threads. The nanowires were applied as the catalyst in СО oxidation with oxygen. The activity of Au–Cu nanowires deposited on glass filters was compared with that for monometallic and bimetallic Au and Cu particles (3–8 nm in diameter) deposited on alumina by traditional deposition–precipitation and impregnation techniques. The apparent activation energies of the reaction (
Еа
) were 95 and 98, 150, and 147 kJ/mol for Au–Cu nanowires and Au–Cu, Au, and Cu particles, respectively. During running-in of the Au–Cu nanowire–based catalyst,
Еа
decreased to 20 kJ/mol and retained at this level in the subsequent cycles of lowering and raising the reactor temperature.
Criteria of structured and unstructured mesh generation for turbulence models taking into account laminar-turbulent transition were developed using flat plate boundary layer flow. It is shown the ...first near wall cell should be placed in the viscous sublayer in the transition region and stretching factor should not exceed 1.4. For the unstructured meshes all the boundary layer should be covered by prismatic layers. The results of the prediction of the flow around a NLF(1)-0414F airfoil show that the use of relatively coarse meshes provide acceptable accuracy of the solution.
A boron-doped diamond electrode with a network structure of PdNi alloy nanowires, which is deposited onto its surface by laser ablation in superfluid helium, is considered as a possible sensor for ...formaldehyde. It is shown that the electrode is highly sensitive to trace amounts of formaldehyde.
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