The article investigated the process of penetration of an aluminum plate by a steel ball at speeds from 600 to 1000 m/s. A numerical simulation of the impact of the ball was carried out and compared ...with the results of experiments in which the ball was accelerated using a powder accelerator. Numerical models were developed using the explicit finite element method in LS-DYNA software. The influence of material properties and model parameters on the penetration process is analyzed. A good agreement between numerical and experimental results has been achieved.
In the majority studies of materials produced by Spark Plasma Sintering (SPS), the powders are consolidated in graphite dies using graphite punches and protective graphite foil. As a result, carbon ...uptake by the sintered material can occur. In this study, a Ni–15 at% W alloy was studied in this context for the first time and was chosen as a suitable model system, in which tungsten forms stable carbides whereas nickel does not, but offers a medium for carbon diffusion into the interior of the compact. In a disk-shaped 3 mm-thick compact Spark Plasma Sintered at 900 °C, carbon uptake resulted in the formation of tungsten carbide WC particles ranging from 0.2 to 2 μm in the subsurface layers of the compact (within distances 50–100 μm from the interface with the foil). The size of the WC particles varied with distance, smaller particles forming in the vicinity of the interface—in the area in which the nucleation was favoured at high carbon concentrations. However, it was not only the subsurface layer that was affected by the presence of carbon: particles of Ni 2 W 4 C were found at depths greater than 100 μm from the interface and throughout the volume of the compact. The distribution of the submicron WC particles and particles of Ni 2 W 4 C corresponded to a network of boundaries between the agglomerates of the Ni–W powder that was consolidated into a compact. These boundaries offered paths for faster diffusion of carbon from the foil when compared with the volume of the agglomerates. The carbide subsurface layer dramatically changed the interdiffusion behaviour of the sintered material in a pair with aluminum due to a significantly reduced concentration of tungsten capable of diffusing within a metallic phase.
The paper presents a numerical discrete element model of granule consolidation taking into account only the elastic interaction force. Calculation of electric and temperature fields was added to the ...model. Granules are considered as a set of nodes with links in between. Using this model, numerical experiments were carried out, the results of which qualitatively show the process of granular material consolidation.
An implementation of carbon nanotube films in optoelectronic devices is still a challenging task which requires further improvement of their both optical and electrical properties. Here, we report an ...approach to enhance the transmittance of single-walled carbon nanotube films placed onto polymeric substrates without losses in the film conductivity by a low-power laser treatment. Laser pulses facilitate oxidation of nanotube caps thereby exposing iron catalytic particles due to fast local heating which leads to the oxidation of iron whereas the nanotube structure generally remains intact. Thus, we approached transmittance enhancement mainly across the visible range up to 4% (at 550 nm) associated with equivalent sheet resistance improvement of ca. 21%.
Display omitted
•Laser treatment is applied to carbon nanotube films placed over polymeric substrate to improve optoelectronic properties.•Carbon nanotube structure remains almost intact.•Low power laser irradiation facilitates 21%-gain of film equivalent sheet resistance.•Carbon nanotube film transmittance increases due to nanotube caps' and catalyst oxidation.
Many natural substances exhibit anti-inflammatory activity and considerable potential in prophylaxis and treatment of allergies. Knowing exact molecular targets, which is required for developing ...these as medicinal products, is often challenging for multicomponent compositions.
In the present study we examined novel polyphenolic substance, a water-soluble fraction of wood lignin (laboratory code BP-Cx-1). In our previous study, a number of polyphenolic components of BP-Cx-1 (flavonoids, sapogenins, phenanthrenes etc.) were identified as the major carriers of biological activity of BP-Cx drug family, and several molecular targets involved in cancer and/or inflammation signaling pathways were proposed based on the results of the in vitro and in silico screening studies.
In the present study, half maximal inhibitory concentration (IC50) of BP-Cx-1 was established with a radioligand method and a range of IC50 values between 22.8 and 40.3 μg/ml were obtained for adenosine receptors A1, A2A and prostaglandin receptors EP2, IP (PGI2). IC50 for serotonin 5-HT1 and for glucocorticoid GR receptors were 3.0 μg/ml and 12.6 μg/ml, respectively, both being within the range of BP-Cx-1 concentrations achievable in in vivo models.
Further, distribution of 3H labelled BP-Cx-1 in NIH3T3 murine fibroblasts and MCF7/R carcinoma cells was studied with autoradiography. 3H-BP-Cx-1 (visualized as silver grains produced by tritium beta particles) was mainly localized along the cell membrane, in the perinuclear region and in the nucleus, suggesting ability of BP-Cx-1 to enter cells and bind to membrane or cytosol receptors.
In our experiment, we observed the effect of BP-Cx-1 on maturation of dendritic cells (DCs): downregulation of expression of the lipid-presentation molecule CD1a, co-stimulatory molecules CD80, CD83 and CD 40, decreased production of pro-inflammatory cytokines IL-4 and TNF-α and increased production of anti-inflammatory cytokine IL-10. It is hypothesized that 3H-BP-Cx-1 detectable in the nucleus is part of the activated GR complex, known to be involved in regulation of transcription of genes responsible for the anti-inflammatory response. Based on IC50, cell distribution data and results of the experiment with DCs it is suggested that the in vivo effects of BP-Cx-1 are mediated via GR and 5-HT1 receptors thus promoting development of tolerogenic effector function in dendritic cells.
•Water-soluble fraction of wood lignin (BP-Cx-1) targets GR and 5-HT1 receptors.•3H-BP-Cx-1 is detectable on cell membranes, perinuclear region and cell nucleus.•Effects of BP-Cx-1 on dendritic cells resemble those of corticosteroids or serotonin.•BP-Cx-1 induces tol-DCs, reported to play a role in treatment of autoimmune diseases.
The work is devoted to the study of the movement of a vibration-driven robot of a circular cross section in a viscous incompressible fluid, induced by the plane polyharmonic oscillations of the ...internal mass. The fluid flow is described by the system of Navier–Stokes equations, which is solved analytically by the method of asymptotic expansions for the case of small ratios of the internal mass to the total mass of the robot. For cruising regime of motion, when the average hydrodynamic force acting on the vibration-driven robot is equal to zero, the dependence of the average speed on the dimensionless oscillation parameters is found. Optimal parameters of motion are investigated.
Magnetic pulse welding differs from explosive welding only by sources of energy for sheet acceleration: magnetic field energy is used instead of explosion energy. Magnetic field interaction with the ...sheet has some specific features associated with the value of energy stored in the battery, the rate of heating to the melting point, and the possibility of sheet buckling, which impose constraints on using magnetic pulse welding. These constraints are associated with geometric parameters of the welded sheets and the gaps between them; the critical values of these parameters are obtained in the present study. A capacitor battery is used in the experiments for sheet acceleration. A new pioneering scheme of magnetic pulse welding of more than two sheets is developed.
Pulmonary edema is the major factor of tissue hypoxia in acute lung injury. Disruption of cell—cell contacts and lung interstitium increases permeability of the vascular endothelium and alveolar ...epithelium, which leads to the development of pulmonary edema. Meprin metalloproteases cleave extracellular matrix proteins, thus aggravating pulmonary edema. Meprin inhibitor actinonin was administered to rats with LPS-induced acute lung injury. Damaged lungs looked spotted and had multiple hemorrhage focuses, protein concentration in lavage fluid was increased, and lung weight coefficient was high. Administration of meprin inhibitor actinonin considerably reduced protein content in the bronchoalvelolar lavage and lung coefficient; only solitary lung hemorrhages were seen after this treatment. Thus, inhibition of meprins potentially alleviates LPS-induced disorders in the lung tissue permeability and reduces pulmonary edema.
The emergence of nano dielectrics for specialized high voltage applications sparked off a variety of research activities, which proved that nano-fillers are capable of improving the electrical, ...thermal and mechanical properties of polymers. This paper primarily investigates the effect of addition of hBN (hexagonal boron nitride) nanoparticles into an epoxy polymer base by increasing fill-grade, from 0.2 to 5 % by volume, from two different standpoints: (a) characterizing the electrical space charge (S.C.) accumulation threshold under DC electrical fields, and, (b) demonstrating the alterations in material properties of the modified polymeric materials, from the unfilled polymer. Objective (a) is experimentally investigated by the pulsed electro-acoustic (PEA) technique, well known for determining spatial charge distribution in dielectrics. Objective (b) is investigated by determining the ultrasonic velocity response of the modified composites and unfilled polymer. The obtained results suggest a relation between electrical threshold fields for S.C. accumulation & fill-grades, as well as the fact that incorporating stiff filler materials into brittle polymer bases leads to a tougher composite (capable of withstanding greater breaking stress levels), but with reduced ductility.
Plastoquinone, a very effective electron carrier and antioxidant of chloroplasts, was conjugated with decyltriphenylphosphonium to obtain a cation easily penetrating through membranes. This cation, ...called SkQ1, is specifically targeted to mitochondria by electrophoresis in the electric field formed by the mitochondrial respiratory chain. The respiratory chain also regenerates reduced SkQ1H(2) from its oxidized form that appears as a result of the antioxidant activity of SkQ1H(2). SkQ1H(2) prevents oxidation of cardiolipin, a mitochondrial phospholipid that is especially sensitive to attack by reactive oxygen species (ROS). In cell cultures, SkQ1 and its analog plastoquinonyl decylrhodamine 19 (SkQR1) arrest H(2)O(2)-induced apoptosis. When tested in vivo, SkQs (i) prolong the lifespan of fungi, crustaceans, insects, fish, and mice, (ii) suppress appearance of a large number of traits typical for age-related senescence (cataract, retinopathies, achromotrichia, osteoporosis, lordokyphosis, decline of the immune system, myeloid shift of blood cells, activation of apoptosis, induction of β-galactosidase, phosphorylation of H2AX histones, etc.) and (iii) lower tissue damage and save the lives of young animals after treatments resulting in kidney ischemia, rhabdomyolysis, heart attack, arrhythmia, and stroke. We suggest that the SkQs reduce mitochondrial ROS and, as a consequence, inhibit mitochondria-mediated apoptosis, an obligatory step of execution of programs responsible for both senescence and fast "biochemical suicide" of an organism after a severe metabolic crisis.
