Three-dimensional numerical simulation of a detonation wave propagating in a circular tube filled with a gas suspension of aluminum particles in oxygen is performed using the HyCFS-R code developed ...by the authors for modeling on hybrid computational systems. The regime of propagation with a single-head spin is reproduced. It is shown that combustion occurs in a certain localized front zone rotating during front propagation, which is typical for spin detonation in both purely gaseous mixtures and heterogeneous media. Data on the basic parameters of detonation wave propagation in a gas suspension of aluminum particles in the spin detonation mode are obtained. Comparisons with theoretical predictions and with numerical and experimental results of other researchers are performed.
Annual fish of the genus
are promising models for aging research.
reproduces typical aspects of vertebrate aging, including hallmarks of brain aging. Meclofenoxate (MF) is a well-known compound that ...can enhance cognitive performance. The drug is prescribed for asthenic conditions, trauma, and vascular diseases of the brain. It is believed that MF is able to delay age-dependent changes in the human brain. However, until now, there has been no study of the MF effect on the brain transcriptome. In the present work, we performed an RNA-Seq study of brain tissues from aged
, which were almost lifetime administered with MF, as well as young and aged control fish. As expected, in response to MF, we revealed significant overexpression of neuron-specific genes including genes involved in synaptic activity and plasticity, neurotransmitter secretion, and neuron projection. The effect was more pronounced in female fish. In this aspect, MF alleviated age-dependent decreased expression of genes involved in neuronal activity. In both treated and untreated animals, we observed strong aging-associated overexpression of immune and inflammatory response genes. MF treatment did not prevent this effect, and moreover, some of these genes tended to be slightly upregulated under MF treatment. Additionally, we noticed upregulation of some genes associated with aging and cellular senescence, including isoforms of putative vascular cell adhesion molecule 1 (VCAM1), protein O-GlcNAcase (OGA), protein kinase C alpha type (KPCA), prolow-density lipoprotein receptor-related protein 1 (LRP1). Noteworthy, MF treatment was also associated with the elevated transcription of transposons, which are highly abundant in the
genome. In conclusion, MF compensates for the age-dependent downregulation of neuronal activity genes, but its effect on aging brain transcriptome still cannot be considered unambiguously positive.
The problem of the supersonic flow of a viscous compressible gas over a flat plate at a zero angle of attack was numerically studied. The two-dimensional Navier–Stokes equations were solved at ...various Reynolds numbers on adaptive grids with boundary-layer mesh refinement. Well-known grids constructed with the help of coordinate transformations eliminating boundary layers of various types were considered. The characteristics of numerical solutions (the value and order of the error, the value and order of the solution jump, and computation time) were analyzed in a series of numerical experiments. The advantages, shortcomings, and the applicability of each boundary layer mesh refinement rule for finding the numerical solution of this problem were discussed. The novelty of this work lies in the analysis of special adaptive grids and their use for solving problems applied in various fields of supersonic aero- and gas dynamics.
Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging ...and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml
. Efficient uptake of the NPs by cancer cells was found using bioimaging in the optical transmittance and photoluminescence modes. Treatment of the cells with uptaken SiNPs by therapeutic ultrasound for 5-20 min resulted in a strong decrease in the number of living cells, while the total number of cells remained nearly unchanged. The obtained data indicate a 'mild' effect of the combined action of ultrasonic irradiation and SiNPs on cancer cells. The observed results reveal new opportunities for controlling the photoluminescent and sonosensitizing properties of silicon-based NPs for applications in the diagnostics and mild therapy of cancer.
Threshold π- photoproduction on the neutron Briscoe, W. J.; Kudryavtsev, A. E.; Strakovsky, I. I. ...
The European physical journal. A, Hadrons and nuclei,
08/2020, Letnik:
56, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Recent data from the PIONS@MAX-lab Collaboration, measuring the total cross section of the incoherent pion photoproduction reaction,
γ
d
→
π
-
p
p
, near threshold, have been used to extract the
E
0
...+
multipole and total cross section of the reaction
γ
n
→
π
-
p
, also near threshold. These are the first measurements of the reaction
γ
d
→
π
-
p
p
in the threshold region. The value of
E
0
+
is extracted through a fit to the deuteron data in a photoproduction model accounting for final-state interactions. The model takes an
S
-wave approximation for the elementary reaction
γ
n
→
π
-
p
with
E
0
+
=
const in the threshold region. The fit over all the 6 deuteron data points gives the value
E
0
+
=
-
31.86
±
0.8
(in units
10
-
3
/
m
π
). We explore the dependence of our results on the choice of data subsets included in the fit. The obtained values of
E
0
+
, for different subsets, have overlapping errors and agree with previous determinations.
The Direct Simulation Monte Carlo (DSMC) method is used to study rarefaction effects on the structure of an axisymmetric underexpanded jet. A comparison with the data of other researchers shows that ...DSMC simulations accurately reproduce the features of the steady shock-wave structure of the jet. Rarefaction produces a noticeable effect on the jet flow. In particular, it makes the barrel shock in the first shock cell change the type of its reflection from the axis, which leads to vanishing of the developed Mach disk and to the changes in the structure of other shock cells. For the first time, the formation of a closed reverse flow region behind the Mach disk is observed in a molecular-kinetic simulation. This phenomenon has been earlier observed only in continuum simulations.
The Direct Simulation Monte Carlo method is used to study the emergence and development of the Rayleigh-Taylor instability. At the initial time, the heavier gas (argon) was located above the lighter ...gas (helium). In the simulation, no initial perturbations were superimposed on the interface, the appearance of instability was caused by fluctuations of gas- dynamic parameters that are inherent in the Direct Simulation Monte Carlo calculations. The onset of large-scale movement and mixing processes are investigated. Quantitative characteristics of the evolution of the Rayleigh-Taylor instability in a rarefied mode are obtained.
The development of instabilities in supersonic perfectly expanded jets exhausting from nozzles with square and rectangular cross sections into an ambient flow is studied based on the numerical ...solution of the Navier–Stokes equations. The simulations are performed for various Mach numbers of the jet and the ambient flow. The results of numerical calculations make it possible to identify qualitative and quantitative differences in instability development in cases with supersonic and subsonic air flows, as well as characteristic features of the flow for rectangular jets.
Epitaxial layers in a system of InAs
1–
x
–
y
Sb
y
P
x
solid solutions in the composition range of 0 <
x
< 0.72 were obtained on an InAs(001) substrate by metalorganic vapor phase epitaxy (MOVPE). ...The layer-by-layer analysis of obtained structures by secondary ion mass spectrometry showed a gradient change in the composition along the growth direction. A dramatic change in the composition at the layer/substrate heteroboundary was observed for the quaternary InAsSbP solid solutions due to the presence of radicals of arsenic compounds in the gas phase. Upon MOVPE deposition on the InAs substrate in a system of InAsSbP solid solutions, the decrease in the solid-phase content of arsenium by less than (1–
x
–
y
) < 0.3 resulted in a suppression of the deposited layer gradientness, as well as suppressed fluctuations in the composition in the initial transition layer.
—The effect of annealing temperature on the structure, texture, and mechanical properties of the austenitic 08Kh16N13M2T stainless steel after cold radial forging to a degree of 95% has been ...investigated. Preliminary plastic deformation results in the formation of austenitic structural and 〈111〉 and 〈100〉 textural gradients. Low-temperature annealing (500–600°C) causes structural polygonization. The intensity of the 〈111〉 and 〈100〉 textural components remains unchanged. Annealing at 700°С initiates recrystallization only in the surface layers of the bar. Annealing at 800–900°C results in static recrystallization processes throughout the bar cross section, which blurs the textural gradient. Annealing at 400–600°C increases the strength and hardness properties. Moreover, the plasticity increases with increasing annealing temperature. Annealing at 700°C makes the material soften almost to the level of the initial cold-deformed state and significantly increases its plasticity.
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