ABSTRACT We investigate quasi-adiabatic dynamics of charged particles in strong current sheets (SCSs) in the solar wind, including the heliospheric current sheet (HCS), both theoretically and ...observationally. A self-consistent hybrid model of an SCS is developed in which ion dynamics is described at the quasi-adiabatic approximation, while the electrons are assumed to be magnetized, and their motion is described in the guiding center approximation. The model shows that the SCS profile is determined by the relative contribution of two currents: (i) the current supported by demagnetized protons that move along open quasi-adiabatic orbits, and (ii) the electron drift current. The simplest modeled SCS is found to be a multi-layered structure that consists of a thin current sheet embedded into a much thicker analog of a plasma sheet. This result is in good agreement with observations of SCSs at ∼1 au. The analysis of fine structure of different SCSs, including the HCS, shows that an SCS represents a narrow current layer (with a thickness of ∼104 km) embedded into a wider region of about 105 km, independently of the SCS origin. Therefore, multi-scale structuring is very likely an intrinsic feature of SCSs in the solar wind.
We have reported the density functional theory investigations on the monolayered, 2 layered and bulk MoSi2N4 in three structural modifications called α1 Y.-L. Hong, et al., Chemical Vapor Deposition ...of Layered Two-Dimensional MoSi2N4 Materials, Science, 2020, 369(6504), 670–674, DOI: 10.1126/science.abb7023, α2 and α3 Y. Yin, Q. Gong, M. Yi and W. Guo, Emerging Versatile Two-Dimensional MoSi2N4 Family, Adv. Funct. Mater., 2023, 2214050, DOI: 10.1002/adfm.202214050. We showed that in the case of monolayers the difference in total energies is less than 0.1 eV between α1 and α3 phases, and less than 0.2 eV between α1 and α2 geometries. The most energetically favorable layer stacking for the bulk structures of each phase was investigated. All considered modifications are dynamically stable from a single layer to a bulk structure in energetically favorable stacking. Raman spectra for the monolayered, 2 layered and bulk structures were simulated and the vibrational analysis was performed. The main difference in the obtained spectra is associated with the position of the strongest band which depends on the Mo–N bond length. According to the obtained data, we can conclude that the Raman line at 348 cm−1 in the experimental spectra of MoSi2N4 can have more complex explanation than just Γ-point Raman-active vibration as was discussed before in Y.-L. Hong, et al., Chemical Vapor Deposition of Layered Two-Dimensional MoSi2N4 Materials, Science, 2020, 369(6504), 670–674, DOI: 10.1126/science.abb7023.
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•Pectins from E. sylvaticum and E. arvense have similar structure.•Horsetail pectins mainly composite of HG regions with minor low branched RG regions.•Horsetail pectins are partially ...acetylated in low methyl-esterified HG regions.•Pectin EA forms stronger ionotropic gel than pectin ES.•Anti-DPPH activity of pectin EA is higher than pectin ES.
The pectins were isolated from sterile stems of E. arvense (EA, yield 5.9%) and E. sylvaticum (ES, yield 4.8%) (Equisetaceae) using ammonium oxalate extraction after preliminary treatment with dilute HCl (рH 4.0). The pectins possessed high molecular weight (Mw, 340–360 kDa), high GalA content (ca. 85%), low degrees of methyl-esterification (14–16%) and acetylation (3–8%). NMR analysis indicated extensive regions of partially methyl-etherified and 3-O-acetylated HG and minor regions of low branched RG in the fragment isolated after hydrolysis of pectin EA by pectinase. Pectin EA produced a higher viscosity solution, formed a stronger and more rigid ionotropic hydrogel than pectin ES. The pectins scavenged DPPH and hydroxyl radicals, but not the superoxide radical and hydrogen peroxide. Phenolic compounds (0.11 and 0.23%) associated with polysaccharide moieties were apparently responsible for the differences in the anti-DPPH scavenging activity of pectins EA and ES (63 and 49%). The findings suggested that pectin from E. arvense should be more perspective than pectin from E. sylvaticum on their use as components of wound healing remedies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•An effective oval-trench dimple for vortex heat transfer enhancement is offered.•The modified SST model using Rodi–Leschziner–Isaev’s approach is applied.•Oval dimples of fixed spot area and ...variable length are grouped.•Separated flow restructuring by narrowing and lengthening the dimple is found.•Thermal/thermal-hydraulic efficiency of a narrow dimpled channel is analyzed.
The article is devoted to the analysis of vortex heat transfer enhancement due to the use of oval-trench dimples. The main role in the understanding of this process is associated with the application of the technologies developed in engineering practice thanks to design decisions. As a result, prevailing interest has been paid to a spherical dimple when a spot diameter is chosen as a characteristic size, whereas hydraulic losses depend on the dimple-to-device size ratio. Progress in vortex heat transfer enhancement due to the use of oval dimples is connected with the explanation of the mechanism of generation of both vortex structures in dimples and spiral vortices behind them. An abrupt increase of heat transfer in the vicinity of the spherical dimple due to the restructuring of the flow structure in the dimple with two vortices to that in the dimple with one spiral vortex made it possible to propose a new shape of a surface vortex generator – an oval dimple located at an angle of inclination to the incoming flow and consisting of two spherical dimple halves separated by a cylindrical insert. The generation of vortex structure in this case is rather stable and intense in comparison to spherical dimple. The numerical results for vortex heat transfer enhancement in the turbulent water flow in the rectangular narrow channel with spherical, 10°-truncated conical and oval dimples of the same spot area and depth at the heated wall are presented. In the article, central attention is given to the mechanism of secondary flow restructuring and heat transfer enhancement due to increase in a relative length and width of an oval dimple followed by the formation of a long spiral vortex in it. The change in the length of the oval dimple (in terms of its width) from 1 to 6.78 allowed one to rationally mount spiral vortex surface generators in the narrow channel with high thermal and thermal-hydraulic efficiencies, significantly exceeding the identical characteristics of channels with spherical and conical dimples. In this case, moderate hydraulic losses in the channel with an oval-trench dimple, when its length is increased to 6.78, are comparable to those in the channel with a basic spherical dimple.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Scintillation of pulsar radio signals caused by the interstellar medium can in principle be used for interstellar interferometry. Changes in the dynamic spectra as a function of pulsar ...longitude were in the past interpreted as having spatially resolved the pulsar magnetosphere. Guided by this prospect we used very long baseline interferometry observations of PSR B1237+25 with the Arecibo and Green Bank radio telescopes at 324 MHz and analyzed such scintillation at separate longitudes of the pulse profile. We found that the fringe phase characteristics of the visibility function changed quasi-sinusoidally as a function of longitude. Also, the dynamic spectra from each of the telescopes shifted in frequency as a function of longitude. Similar effects were found for PSR B1133+16. However, we show that these effects are not signatures of having resolved the pulsar magnetosphere. Instead, the changes can be related to the effect of low-level digitizing of the pulsar signal. After correcting for these effects the frequency shifts largely disappeared. Residual effects may be partly due to feed polarization impurities. Upper limits for the pulse emission altitudes of PSR B1237+25 would likely be well below the pulsar light cylinder radius. In view of our analysis, we think that observations with the intent of spatially resolving the pulsar magnetosphere need to be critically evaluated in terms of these constraints on interstellar interferometry.
Summary
The objective of this study was to test the capacity of a newly developed fusion protein of interleukin 4 (IL‐4) and IL‐10 IL4‐10 fusion protein (FP) to shift multiple pro‐inflammatory ...pathways towards immune regulation, and to inhibit pro‐inflammatory activity in arthritis models. The effects of IL4‐10 FP in comparison with IL‐4, IL‐10 and IL‐4 plus IL‐10 on pro‐ and anti‐inflammatory mediators, T cells and immunoglobulin (Ig) receptors in favour of immunoregulatory activity were studied. In addition, the capacity of IL4‐10 FP to inhibit pro‐inflammatory activity in ex‐vivo and in‐vivo arthritis models was investigated. IL4‐10 FP robustly inhibited pro‐inflammatory cytokine IL‐1β, tumour necrosis factor (TNF)‐α, IL‐6 and IL‐8 production in whole blood cultures, mediated by both the IL‐10 and the IL‐4 moiety. IL4‐10 fusion protein induced IL‐1 receptor antagonist (IL‐1RA) production and preserved soluble TNF receptor (sTNFR) levels, strongly increasing IL‐1RA/IL‐1β and sTNFR/TNF‐α ratios. In addition, IL4‐10 FP strongly inhibited T helper (Th) type 1 and 17 cytokine secretion, while maintaining FoxP3 expression and up‐regulating Th2 activity. In addition, while largely leaving expression of activating Fc gamma receptor (FcγR)I, III and Fc epsilon receptor (FcεR) unaffected, it significantly shifted the FcγRIIa/FcγRIIb ratio in favour of the inhibitory FcγRIIb. Moreover, IL4–10 FP robustly inhibited secretion of pro‐inflammatory cytokines by rheumatoid arthritis synovial tissue and suppressed experimental arthritis in mice, without inducing B cell hyperactivity. IL4‐10 fusion protein is a novel drug, signalling cells to induce immunoregulatory activity that overcomes limitations of IL‐4 and IL‐10 stand‐alone therapy, and therefore has therapeutic potential for inflammatory diseases such as rheumatoid arthritis.
IL4‐10 fusion protein (IL4–10 FP) combines two potent anti‐inflammatory cytokines with unique properties into one molecule. IL4‐10 FP signals cells to induce robust immunoregulatory activity, strongly inhibiting pro‐inflammatory cytokine production by RA synovial tissue explants and suppressing experimental arthritis in mice. IL4‐10 fusion protein overcomes limitations of IL‐4 and IL‐10 stand‐alone therapy and therefore has therapeutic potential for the treatment of inflammatory diseases.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
•The fluctuation mechanism of the internal friction in Ba0.8Sr0.2TiO3 was discovered.•The internal friction peak increases under a dc electric field.•Losses are due to the interaction of charged ...point defects with domain walls.•Doping with La atoms changes the internal friction.
The temperature dependences of internal friction and Young’s modulus in ferroelectric Ba0.8Sr0.2TiO3 ceramics under bending oscillations were investigated at frequencies of the several hertz. The effect of the heating rate and the frequency of oscillations on the internal friction peak height near the Curie temperature was studied. The fluctuation model of low-frequency internal friction is used to explain the obtained dependences and to estimate the nuclei volume of a new phase arising at a phase transition. After a dc electric field switched on in the ferroelectric phase, the time decrease of internal friction was observed, which had an exponential form. The addition of 0.2 mass. % La in Ba0.8Sr0.2TiO3 led both to an increase in the internal friction level in the ferroelectric phase and to a decrease in the internal friction maximum near the Curie temperature. In the first case, this was explained by a decrease in the interaction energy of charged point defects with ferroelectric domain walls, and in the second case, by the pinning of domain walls by lanthanum ions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Relevance. In recent years, the oil industry has seen a tendency to transfer low-yield oil wells to intermittent mode. Unregulated electric drive and the open-loop controlled electric drive of ...electric centrifugal pumping with permanent magnet synchronous motors are typically not suitable for tasks of intermittent operation of wells. Due to objective reasons, there may not be smooth starts and required quality indicators of transient processes, which leads to even more reduction in oil production. The synthesis of a closed-loop electric drive control system of submersible installations is possible only using algorithms for indirect estimation of non-measured mechanical coordinates of the electric drive – state variables identification methods, observers of the rotor angular velocity and the load torque. The installation of sensors of angular velocity and torque on the shaft of the submersible electric motor is associated with technical difficulties, therefore, there is no need for significant modernization of the hardware solutions of the existing electrical equipment system. To date, the theory of identifying non-linear dynamic systems is widely used to derive an indirect estimate of the non-measured state variables of the permanent magnet synchronous motors. The large number of methods presented in scientific sources requires comparative analysis regarding their benefits and disadvantages in order to select the best identification method that meets the requirements of the oil production and takes into account its specificity and features. In this case, identification systems that are focused on minimizing computing power or operating in real time are given priority. Aim. To determine the best in terms of computational complexity and the convenience of practical use method of identifying state variables of permanent magnet synchronous motors operating in submersible oil well pumping units based on comparative analysis of existing methods presented in Russian and foreign sources. Methods. Methods for system analysis and identification of dynamic systems, a method of critical expert analysis. Result and conclusions. The most common methods for identifying and observing the state variables of synchronous motors with permanent magnets have been described in detail, given the general performance of each group of methods, their benefits and disadvantages were reviewed. By comparative critical expert analysis, it was found that for tasks of submersible electric centrifugal pump units electric drive a Luenberger observer, characterized by relatively low computational complexity and ease of setup in engineering practice can be recommended.
Anionic liposomes were electrostatically adsorbed onto the surface of cationic chitosan particles cross-linked by sulfate anions, forming multi-liposomal containers (MLCs) for encapsulation and ...delivery of bioactive substances. An increase in molecular mass of chitosan from 30 to 300 kDa results in a size increase of chitosan particles, from 200 to 400 nm. Being saturated by liposomes, chitosan particles give MLCs of 320–540 nm. Each chitosan particle carries between 60 and 200 liposomes. The proteolytic complex Morikrase, a mixture of enzymes with various specificities, induces degradation of MLCs down to particles of size 10–15 nm; the higher the molecular mass of chitosan, the slower the enzyme-induced MLCs' degradation. pH variation within 5.5–7 and cholesterol incorporation into the liposomal membrane both have a minor effect on the rate of MLCs' biodegradation. Both the MLCs and the products of their biodegradation show low cytotoxicity. These results are of interest for constructing biodegradable capacious carriers of bioactive substances.
•Liposomes were adsorbed on chitosan particles forming multi-liposomal complexes (MLCs).•MLCs degraded, being attacked by proteolytic enzymes, down to 10–15 nm particles.•The longer chitosan macromolecules, the slower enzyme-induced degradation of MLC.•Variation in pH and cholesterol incorporation had slight effect on biodegradation rate.•MLCs and products of their biodegradation demonstrated low cytotoxicity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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