In this article, we discuss the extension of the Melvin solution for the geon to some models of non-linear electrodynamics with the exact form of the Lagrangian, in particular, for a conformally ...invariant model (CNED), whose Lagrangian depends on the second and fourth order invariants of the electromagnetic field tensor.
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.
We report the early discovery of the optical afterglow of gamma-ray burst (GRB) 140801A in the 137 deg2 3-σ error-box of the Fermi Gamma-ray Burst Monitor (GBM). MASTER is the only observatory that ...automatically reacts to all
Fermi alerts. GRB 140801A is one of the few GRBs whose optical counterpart was discovered solely from its GBM localization. The optical afterglow of GRB 140801A was found by MASTER Global Robotic Net 53 s after receiving the alert, making it the fastest optical detection of a GRB from a GBM error-box. Spectroscopy obtained with the 10.4-m Gran Telescopio Canarias and the 6-m Big Telescope Alt-azimuth of the Special Astrophysical Observatory of the Russian Academy of Sciences reveals a redshift of z = 1.32. We performed optical and near-infrared photometry of GRB 140801A using different telescopes with apertures ranging from 0.4 to 10.4 m. GRB 140801A is a typical burst in many ways. The rest-frame bolometric isotropic energy release and peak energy of the burst are
$E_\mathrm{iso} = 5.54_{-0.24}^{+0.26} {\times} 10^{52}$
erg and E
p, rest ≃ 280 keV, respectively, which is consistent with the Amati relation. The absence of a jet break in the optical light curve provides a lower limit on the half-opening angle of the jet θ = 6
$_{.}^{\circ}$
1. The observed E
peak is consistent with the limit derived from the Ghirlanda relation. The joint Fermi GBM and Konus-Wind analysis show that GRB 140801A could belong to the class of intermediate duration. The rapid detection of the optical counterpart of GRB 140801A is especially important regarding the upcoming experiments with large coordinate error-box areas.
The target of this work is the demonstration of advanced approaches able to provide non-silicon MEMS platforms for chemical sensor operating under harsh environmental conditions and, on the other ...hand, to assure microhotplate stable at high temperature, which can be used for the deposition of refractory gas-sensing materials, for example, oxides of gallium, zirconium, or hafnium. Non-silicon materials that can be used for these MEMS platforms include aluminum oxide, yttria-stabilized zirconia and thin borosilicate glass. It was shown that thin ceramic films made of oxide materials can withstand annealing temperature up to 1000°C, MEMS sensor based on these films consumes <70mW at continuous heating at 450°C and ∼1mW in pulsed heating operation mode. Ceramic MEMS show higher stability at high temperature compared to silicon technology based MEMS, whereas power consumption of both types of devices is comparable.
Neutrophil myeloperoxidase (MPO) plays an important role in protecting the body against infections. MPO products–hypohalous acids and phenoxyl radicals–are strong oxidants that can damage not only ...foreign intruders but also host tissues, including blood plasma proteins. Here, we compared the MPO-induced oxidation of two plasma proteins with antioxidant properties–human serum albumin (HSA) and ceruloplasmin (CP). Incubation of both proteins with hypochlorite (NaOCl) or catalytically active MPO (MPO + H
2
O
2
), which synthesizes hypochlorous acid (HOCl) in the presence of chloride ions, resulted in the quenching of protein tryptophan fluorescence. Oxidation-induced changes in the structures of HSA and CP were different. HSA efficiently neutralized MPO-generated oxidants without protein aggregation, while CP oxidation resulted in the formation of large aggregates stabilized by strong covalent bonds between the aromatic amino acid residues. Tyrosine is present in the plasma as free amino acid and also as a component of the polypeptide chains of the proteins. The number of tyrosine residues in a protein does not determine its propensity for aggregate formation. In the case of C P, protein aggregation was primarily due to the high content of tryptophan residues in its polypeptide chain. MPO-dependent oxidation of free tyrosine results in the formation of tyrosyl radicals, that do not oxidize aromatic amino acid residues in proteins because of the high rate of recombination with dityrosine formation. At the same time, free tyrosine can influence MPO-induced protein oxidation due to its ability to modulate HOCl synthesis in the MPO active site.
In this paper we consider a special case of vacuum nonlinear electrodynamics with a stress–energy tensor conformal to the Maxwell theory. Distinctive features of this model are the absence of a ...dimensional parameter for the nonlinearity description and a very simple form of the dominant energy condition, which can easily be verified in an arbitrary pseudo-Riemannian space-time with the consequent constraints on the model parameters. In this paper we analyze some properties of astrophysical compact objects coupled to conformal vacuum nonlinear electrodynamics.
Myeloperoxidase (MPO) is a unique heme-containing peroxidase that can catalyze the formation of hypochlorous acid (HOCl). The strong interaction of MPO with low-density lipoproteins (LDL) promotes ...proatherogenic modification of LDL by HOCl. The MPO-modified LDL (Mox-LDL) accumulate in macrophages, resulting in the formation of foam cells, which is the pathognomonic symptom of atherosclerosis. A promising approach to prophylaxis and atherosclerosis therapy is searching for remedies that prevent the modification or accumulation of LDL in macrophages. Lactoferrin (LF) has several application points in obesity pathogenesis. We aimed to study LF binding to Mox-LDL and their accumulation in monocytes transformed into macrophages. Using surface plasmon resonance and ELISA techniques, we observed no LF interaction with intact LDL, whereas Mox-LDL strongly interacted with LF. The affinity of Mox-LDL to LF increased with the degree of oxidative modification of LDL. Moreover, an excess of MPO did not prevent interaction of Mox-LDL with LF. LF inhibits accumulation of cholesterol in macrophages exposed to Mox-LDL. The results obtained reinforce the notion of LF potency as a remedy against atherosclerosis.
Abstract
The picturesque and high conservation value thermal landscapes of the Valley of Geysers feature endothermal (heated by endogenous fluids) soils which support endangered and unique species. ...However, such soils have not been distinguished as a separate taxon within most classification systems. In this study, we described the soil morphology at macro-, meso- and micro-scales, chemistry, mineralogy and vegetation of these landscapes as they are affected by the steam-heated acid-sulfate waters. The studied catenary sequence from exothermal (non-heated) to endothermal soils was characterized by decreasing contents of soil organic carbon, sand fraction, essential nutrients (Ca, K, Mg, Mn and Si), increasing soil acidity, amounts of fine particle-size fractions and contents of trace elements (Al, As, Co, Cr, Cu, Fe, Pb, Ti and V) as well as the development of sodium-sulfate salinity, kaolinization and ferrugination. In phytocenoses supported by endothermal soils, species of order
Rosales
and
Asparagales
were overrepresented among obligate and facultative thermophytes respectively, and species of order
Poales
were underrepresented among facultative thermophytes in relation to the flora of the Valley of Geysers. Phytocenoses on the non-heated Andosols were enriched in
Polypodiopsida
species. The results of our comparative analysis of the thermally-induced variability in the soils and vegetation contribute to the general understanding of mineralogical, bio-abiotic and biological systems affected by steam-heated acid-sulfate waters. We hope that our findings will provide a basis for future transdisciplinary studies of the influence of steam-heated waters of a hot spring on the thermal landscapes.
PDF
