Enhanced carrier scattering rates in dilute magnetic semiconductors with correlated impurities

In III-V dilute magnetic semiconductors (DMSs) such as Ga$_{1-x}$Mn$_x$As, the impurity positions tend to be correlated, which can drastically affect the electronic transport properties of these materials. Within the memory function formalism we have derived a general expression for the current relaxation kernel in spin and charge disordered media and have calculated spin and charge scattering rates in the weak-disorder limit. Using a simple model for magnetic impurity clustering, we find a significant enhancement of the charge scattering. The enhancement is sensitive to cluster parameters and may be controllable through post-growth annealing.Comment: 4 pages, 3 figure

Aeroacoustic Measurements of the Bell 699 Rotor on the Tiltrotor Test Rig in the National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel

The Tiltrotor Test Rig (TTR) with the Bell 699 Rotor was tested in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel from 2017 to 2018. The primary goal of the test was to understand the operational capabilities of the TTR while also acquiring research data, including acoustic data. A data quality study revealed that the NFAC 40- by 80-Foot Wind Tunnel is an adequate acoustic environment to test the Bell 699 Rotor for helicopter, conversion, and airplane configurations. Representative acoustic data are presented, and selected acoustic data and corresponding test conditions are included

The value of polymorphism + 3725G / C TLR4 gene as a marker of liver fibrosis progression in patients with chronic hepatitis C

As a rule, chronic hepatitis C is manifested by the development of successive stages of liver fibrosis with the formation of eventually cirrhosis and liver cancer. However, in some patients the fibrosis progresses slowly, while in others there is a rapid formation of cirrhosis, which causes high mortality among such patients. According to published data, despite a fairly large number of studies regarding liver cirrhosis in chronic hepatitis C, factors contributing to liver fibrogenesis have not been definitively determined. The available data are quite contradictory. In this article, we review studies have assessed the TLR4 + 3725G/C gene polymorphism as a factor that may influence the rate of fibrotic progression. The research will build new approach for avoiding fast fibrogenesis

Hierarchical accumulation of RyR post-translational modifications drives disease progression in dystrophic cardiomyopathy

Aims Duchenne muscular dystrophy (DMD) is a muscle disease with serious cardiac complications. Changes in Ca2+ homeostasis and oxidative stress were recently associated with cardiac deterioration, but the cellular pathophysiological mechanisms remain elusive. We investigated whether the activity of ryanodine receptor (RyR) Ca2+ release channels is affected, whether changes in function are cause or consequence and which post-translational modifications drive disease progression. Methods and results Electrophysiological, imaging, and biochemical techniques were used to study RyRs in cardiomyocytes from mdx mice, an animal model of DMD. Young mdx mice show no changes in cardiac performance, but do so after ∼8 months. Nevertheless, myocytes from mdx pups exhibited exaggerated Ca2+ responses to mechanical stress and ‘hypersensitive' excitation-contraction coupling, hallmarks of increased RyR Ca2+ sensitivity. Both were normalized by antioxidants, inhibitors of NAD(P)H oxidase and CaMKII, but not by NO synthases and PKA antagonists. Sarcoplasmic reticulum Ca2+ load and leak were unchanged in young mdx mice. However, by the age of 4-5 months and in senescence, leak was increased and load was reduced, indicating disease progression. By this age, all pharmacological interventions listed above normalized Ca2+ signals and corrected changes in ECC, Ca2+ load, and leak. Conclusion Our findings suggest that increased RyR Ca2+ sensitivity precedes and presumably drives the progression of dystrophic cardiomyopathy, with oxidative stress initiating its development. RyR oxidation followed by phosphorylation, first by CaMKII and later by PKA, synergistically contributes to cardiac deterioratio

Efficiency of technology elements for growing winter wheat on typical chernozem

Received: March 15th, 2023 ; Accepted: July 17th, 2023 ; Published: September 1st, 2023 ; Correspondence: [email protected] use of traditional tillage technologies in short-rotational crop rotations increases the cost of agricultural production and has a negative impact on the environment. The research was aimed at establishing and improving the ways winter wheat yield increase in short-rotational crop rotations depending on the efficiency of the main tillage system and fertilizing on typical chernozems s in conditions of unstable moisture in the Forest Steppe of Ukraine. The research was conducted at the Department of Agrochemistry National Scientific Centre Institute of Agriculture of National Academy of Agricultural Scienses at the Panfil Research Station of the National Scientific Center Institute of Agriculture of the National Academy of Agrarian Sciences in a stationary technological experiment, on typical low-humus chernozem in 2 short rotation crop rotations with the following crops rotation: crop rotation 1 - winter rape (Brassica napus L.), winter wheat (Triticum aestivum L), grain maize (Zea mays), spring barley (Hordeum vulgare L); crop rotation 2 - soybean (Glycine max (L.) Merrill), winter wheat (Triticum aestivum L), sunflower (Helianthus annuus), spring barley (Hordeum vulgare L). The article presents the results of research in two short-rotation crop rotations with the placement of winter wheat (Triticum aestivum L) after winter rape (Brassica napus L.) and soybean (Glycine max (L.) Merrill) against the background of two tillage systems: ploughing (25–27 cm) and no-till (direct sowing). The impact of different methods of soil cultivation and fertilizing systems on the humus content and nutrient regime of typical chernozems in the agrocenosis of winter wheat was determined. It was established that in winter wheat, placed after winter rapeseed and soybeans, there is a tendency to increase the humus content under zero tillage up to 15% relative to the control (without fertilizers) and from 5–14% relative to moldboard tillage (25–27 cm ploughing). The most effective in nutrient accumulation was fertilizing system N(90)P2О5(90)K2О(90) applied after rape and after soybean. Respectively, the content of mobile phosphorus compounds increased by 10–18% and potassium by 1.3–2.0 times compared to the control (without fertilizers) with the advantage of no-tillcultivation technology. The given comparative assessment of the yield formation of winter wheat when growing it after different pre-crops showed that the average yield of winter wheat grain in both cultivations on the control option for the soybean pre-crop was 3.55 t ha-1 and 4.00 t ha-1 for rape. The highest increases in grain yield on average over the years of research were provided by the fertilizing system of 50–54% (N(90)P2О5(90)K2О(90)) for growing winter wheat after soybeans and 39–47% (N(90)P2О5(90) K2О(90)) on the winter rape pre-crop with the advantage of moldboard tillage (ploughing) in crop cultivation technologies. The fertilizing system with the introduction of N(16)P2О(16)K2О(16) has the prospect of spreading because, in terms of the formation of typical indicators of chernozem fertility and the yield of winter wheat grain, it approaches technologies with the introduction of N(120)P2О5(90–60)K2О(100–90) with significant cost savings for mineral fertilizers

Політико-правові особливості участі кримських татар у Другій світовій війні

Кириченко Д. Д. Політико-правові особливості участі кримських татар у Другій світовій війні / Д. Д. Кириченко // Правові та інституційні механізми забезпечення розвитку України в умовах європейської інтеграції : матеріали Міжнародної науково-практичної конференції (м. Одеса, 18 травня 2018 р.) У 2-х т. Т. 1 / відп. ред. Г. О. Ульянова. – Одеса : Видавничий дім «Гельветика», 2018. – С. 179-182

Dark-bright magneto-exciton mixing induced by Coulomb interaction in strained quantum wells

Coupled magneto-exciton states between allowed (`bright') and forbidden (`dark') transitions are found in absorption spectra of strained In$_{0.2}$Ga$_{0.8}$As/GaAs quantum wells with increasing magnetic field up to 30 T. We found large (~ 10 meV) energy splittings in the mixed states. The observed anticrossing behavior is independent of polarization, and sensitive only to the parity of the quantum confined states. Detailed experimental and theoretical investigations indicate that the excitonic Coulomb interaction rather than valence band complexity is responsible for the splittings. In addition, we determine the spin composition of the mixed states.Comment: 4 pages, 4 figure

Ultrahigh-Field Hole Cyclotron Resonance Absorption in InMnAs Films

We have carried out an ultrahigh-field cyclotron resonance study of p-type In1-xMnxAs films, with Mn composition x ranging from 0% to 2.5%, grown on GaAs by low-temperature molecular-beam epitaxy. Pulsed magnetic fields up to 500 T were used to make cyclotron resonance observable in these low-mobility samples. The clear observation of hole cyclotron resonance is direct evidence of the existence of a large number of itinerant, effective-mass-type holes rather than localized d-like holes. It further suggests that the p-d exchange mechanism is more favorable than the double exchange mechanism in this narrow gap InAs-based dilute magnetic semiconductor. In addition to the fundamental heavy-hole and light-hole cyclotron resonance absorption appearing near the high-magnetic-field quantum limit, we observed many inter-Landau-level absorption bands whose transition probabilities are stronglydependent on the sense of circular polarization of the incident light.Comment: 8 pages, 10 Postscript figure