Studying the Izborsk-Malskaya Valley, the authors focus on the origin of glaciolacustrine terraces in overdeepened valleys widespread in the Late Valdai (Ostashkov, Weichselian) glaciation areas. In ...the northern part of the Izborsk-Malskaya Valley were found fragments of the terrace (56–57 m a.s.l.). They are adjacent to the lower parts of its slopes and composed of thin-laminated sands. This terrace could be referred to as the alluvial or kame type. Detailed field and laboratory investigations have made it possible to study the thin-laminated sand formation. It was accumulated in the proglacial lake during the Izborsk–Malskaya valley deglaciation. Later, sand strata were divided by water flow causing the fragments to set apart. The incised stream channel should be associated with the larger water flow rather than the modern Obdekh River. It is likely that dissection of the primary glaciolacustrine surface and fluvial erosion in the valley bottom occurred at the bottom during the proglacial lake discharge approximately 13.3 ka (OSL). The ice-dammed lake was drained relatively rapidly. For this reason, the composition and facies in the upper part of the glaciolacustrine deposits are not variable. Furthermore, additional terraces are absent in the incised stream channel. Thus, the terrace has a glaciolacustrine origin, while its slopes – fluvial erosional one. The new data on the terrace formation process in the northwestern part of the East European Plain differ from the current concepts. Along with the previously described mechanisms of glaciolacustrine terrace formation (abrasion activity of former proglacial lakes, gradual downcutting, or ice-contact slope formation of kame terraces), we should bear in mind the possibility of incision powerful water flows during catastrophic discharges of ice-dammed lakes. Our study of the terrace in the Izborsk-Malskaya Valley gives a clear indication that other similar valleys should be thoroughly examined to revise their age and mechanism of terrace formation.
Highlights • Actual spaceflight considerably decreased BCL-XL gene expression in the hypothalamus. • Long-term spaceflight significantly increased BCL-XL gene expression in the hippocampus. • Actual ...spaceflight considerably reduced BCL-XL gene expression in the striatum. • Shuttle cabin housing also considerably reduced BCL-XL gene expression in the striatum. • Long-term spaceflight failed to affect BAX, BDNF, TrkB and p75 gene expression.
Cytochrome (CYP) 450 isoenzymes are the basic enzymes involved in Phase I biotransformation. The most important role in biotransformation belongs to CYP3A4, CYP2D6, CYP2C9, CYP2C19 and CYP1A2. ...Inhibition and induction of CYP isoenzymes caused by drugs are important and clinically relevant pharmacokinetic mechanisms of drug interaction. Investigation of the activity of CYP isoenzymes by using phenotyping methods (such as the determination of the concentration of specific substrates and metabolites in biological fluids) during drug administration provides the prediction of negative side effects caused by drug interaction. In clinical practice, the process of phenotyping of CYP isoenzymes and some endogenous substrates in the ratio of cortisol to 6β-hydroxycortisol in urine for the evaluation of CYP3A4 activity has been deemed to be a quite promising, safe and minimally invasive method for patients nowadays.
The possibility of improving structural qualities of deposited layers such as hardness and wear resistance by introducing titanium into the composition of powder wires of the Fe – C – Si – Mn – Cr – ...W– Vand Fe – C – Si – Mn – Cr – Mo – Ni systems is investigated. The chemical composition, structure, hardness, and wear resistance of layers deposited on steel 09G2S are investigated. The degree of contamination of the layers with non-metallic inclusions is determined. The positive effect of titanium powder additives in the composition of powder wires on the studied characteristics of the deposited layers is shown.
Drilling recovered the upper part (23 m) of the upland loess–paleosol series (LPS) on the right bank of the Kuma River near the Otkaznoe Settlement. Description of cores and laboratory analyses made ...it possible to carry out lithostratigraphic subdivision of the loess sequence in the summary column. Four paleosol units separated by loess horizons are identified. The two lower contiguous paleosols are defined well in the cores by their dark brown color and high values of magnetic susceptibility. The other two paleosols are weakly expressed and identified mainly by variations in the mechanical composition and contents of organic matter and carbonates. Analysis of 13 luminescence dates obtained in two different laboratories (four dates at Karpinsky Russian Research Geological Institute (VSEGEI), St. Petersburg, Russia; nine dates at Leibniz Institute for Applied Geophysics (LIAG), Hannover, Germany) shows that the LPS belongs to the Late Pleistocene and Holocene. Based on the dates, three (two Bayesian and one linear) depth-age models were constructed. The linear model is in better agreement with the stratigraphic sequence and the cross-regional loess correlation. The age of boundaries of the stratigraphic units was calculated, and a preliminary correlation with the marine oxygen isotope stages (MIS) was carried out: soil S0—MIS 1; loess L1LL1—MIS 2; paleosol L1SS1—MIS 3; loess L1LL2—MIS 4; paleosol S1SS1—MIS 5a; loess S1LL1—MIS 5b; paleosol S1SS2—MIS 5c; loess S1LL2—MIS 5d; and paleosol S1SS3—MIS 5e. Calculations of the sedimentation rate yielded the following results: minimum growth rate of the loess sequence in the Holocene (9 cm/ka) and Mikulino time (10 cm/ka); maximum rate, at the end of the middle–beginning of the late Valdaian (79 cm/ka). Pedostratigraphy and compositional variations give grounds for correlating the summary column with the core of reference Borehole-1 drilled in the Otkaznoe Settlement in 1986.
In the current study, we evaluated the effect of presence of gas nanobubbles in water samples on nonstationary stimulated Raman scattering (SRS) of laser pulses and laser-induced optical breakdown. ...The SRS excitation threshold was higher and the optical breakdown threshold was lower in nanobubble-containing water compared to nanobubble-free water. The spectrum of the SRS signal from nanobubble-free water samples was found to differ from that of nanobubble-containing water samples. The SRS spectrum of water without nanobubbles contained only a narrow peak with a maximum near 3410 cm−1, which can be associated with stretching vibrations of water molecules. However, in water with nanobubbles an additional SRS signal in the frequency range of 500-1000 cm−1 with a maximum at 700 cm−1 appeared at certain pump intensities. The intensity of this signal significantly exceeded that with the maximum at 3410 cm−1. To interpret these results, we put forward a hypothesis that the detected effect is related to the huge enhancement caused by the generation of a resonance surface plasmon inside a gas nanobubble during optical breakdown. Under these circumstances, the frequency of plasmon resonance coincides with the Stokes shift frequency, and the plasmon is excited due to the beating of the pump wave and the Stokes wave. An expression for the plasmon resonance frequency as a function of the nanobubble radius was obtained.
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We have studied in detail the structuring of combustion products in the Ti–Al–C system at low carbon concentrations (96 wt % (Ti + Al) + 4 wt % graphite) prepared by self-propagating ...high-temperature synthesis and compared the results to those for carbon-free samples prepared by the same method. A thin (~500 nm) TiC carbide layer has been shown to be formed on the surface of unreacted graphite particles, followed by the growth of the Ti
2
AlC MAX phase, which has a laminate structure. The presence of the Ti
2
AlC phase in the synthesized samples has been confirmed by X-ray diffraction and energy dispersive analysis. TiC has not been detected by X-ray diffraction, presumably because it is present in a small amount.
A material based on a (VCr)
2
AlC solid solution has been obtained for the first time by self-propagating high-temperature synthesis from a powder reaction mixture of vanadium(V) and chromium(III) ...oxides with aluminum and carbon (graphite). The synthesized material has been studied by X-ray diffraction and microstructural analyses. It has been shown that the product also contains vanadium and chromium carbides and intermetallics. The presence of these phases seems to be associated with the nonequilibrium character of the synthesis process due to a short “lifetime” of melt and its fast cooling and crystallization. The synthesized material is an electrical conductor, which demonstrates a metallic character of conductivity throughout the entire measured temperature range of 300–1300 K. The room-temperature specific resistance of the composite material based on a (Cr,V)
2
AlC solid solution is 1.14 µΩ m, which is higher than the specific resistance of the materials based on the Cr
2
AlC and V
2
AlC MAX phases. The microhardness of the synthesized material is 6.9 GPa.
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A lightweight intermetallic alloy containing the ternary phase Al
18
Ti
2
Mg
3
has been prepared for the first time in the Ti–Al–Mg system by self-propagating high-temperature synthesis. In the ...binary system Ti–Al, synthesis has been carried out in the thermal explosion regime, whereas in the ternary system Ti–Al–Mg layer-by-layer combustion synthesis has been performed. The porosity of the synthesized materials is 43.3%, and its density is 2.4 g/cm
3
.
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