Tunneling recombination in spatially inhomogeneous structures

Methods for finding the parameters (energies and capture coefficients for electrons and holes) of the levels involved in the formation of the recombination flux are suggested. The temperature variation of these parameters for AlGaN/InGaN/GaN and InGaN/SiC structures is discussed. The parameters of the levels responsible for tunneling recombination are determined.     

Microsatellite Instability in Russian Patients with Colorectal Cancer

The aim of this study was to determine the characteristics of Russian patients with microsatellite instability (MSI) tumors. MSI in the tumor was determined in 514 patients with colon cancer using PCR and subsequent fragment analysis for five markers (NR21, NR24, BAT25, BAT26, and NR27). In the presence of microsatellite instability, the mismatch repair (MMR) system genes were examined using the NGS and MLPA methods to establish the diagnosis of Lynch syndrome. The overall frequency of MSI tumors was 15%: at stage I—19% (9/48), at stage II—21% (44/213), at stage III—16% (26/160), and at stage IV—2% (2/93). Patients with MSI tumors differed in the age of diagnosis, tumor localization, time of cancer recurrence, and stage of the disease. The overall and disease-free survival of patients whose tumors had MSI status was higher than that of patients with microsatellite-stable status, p = 0.04 and p = 0.02, respectively. Analysis of overall and disease-free survival of patients with Lynch syndrome and patients with sporadic colon cancer, but with MSI status, did not reveal significant differences, p = 0.52 and p = 0.24, respectively. The age of patients with Lynch syndrome was significantly younger than that of patients with sporadic colon cancer whose tumors had MSI status (p < 0.001).     

Periclase-Carbon Components for Use in the Refractory Lining of the Steel-Tapping Channel of a 370-Ton Converter

Tests of periclase-carbon blocks for the converter's steel-tapping channel available from the Kombinat Magnezit JSC were carried out in an oxygen-converter shop at the Magnitogorskii Metal-and-Steel Works JSC. The new refractory materials are shown to have a higher endurance as compared to the conventional periclase blocks, which made it possible to increase the operational efficiency of converters.     

Structure and Catalytic Activity of Poly(Titanium Oxide) Doped by Gold Nanoparticles in Organic Polymeric Matrix

The nanocomposite copolymers of poly(titanium oxide) (PTO) in an organic matrix of poly(hydroxyethyl methacrylate) (HEMA) doped by the Au nanoparticles (NPs) were synthesized in one-pot reaction. The composites were characterized as high optical transparence. It was proved by the SIMS, SAXS, and X-ray diffraction that PTO forms the 6 nm clusters uniformly distributed inside the organic polymer and chemically bonded to it. The AuNPs were formed by the UV irradiation of the copolymers containing the HAuCl₄ embedded into the reaction mixture before the synthesis. The primary structure of the PTO clusters is close to the anatase modification of crystalline TiO₂. This conclusion is made on the basis of agreement between the experimental FTIR spectra of the synthesized copolymers and the calculated IR spectra of the PTO/HEMA fragments calculated by the DFT quantum chemical methods and also by XPA-analysis. The synthesized materials have high photocatalytic activity. It has been shown by methylene orange decomposition under UV irradiation.     

Inhibition of Neuronal Necroptosis Mediated by RIPK1 Provides Neuroprotective Effects on Hypoxia and Ischemia In Vitro and In Vivo

Ischemic brain injury is a widespread pathological condition, the main components of which are a deficiency of oxygen and energy substrates. In recent years, a number of new forms of cell death, including necroptosis, have been described. In necroptosis, a cascade of interactions between the kinases RIPK1 and RIPK3 and the MLKL protein leads to the formation of a specialized death complex called the necrosome, which triggers MLKL-mediated destruction of the cell membrane and necroptotic cell death. Necroptosis probably plays an important role in the development of ischemia/reperfusion injury and can be considered as a potential target for finding methods to correct the disruption of neural networks in ischemic damage. In the present study, we demonstrated that blockade of RIPK1 kinase by Necrostatin-1 preserved the viability of cells in primary hippocampal cultures in an in vitro model of glucose deprivation. The effect of RIPK1 blockade on the bioelectrical and metabolic calcium activity of neuron-glial networks in vitro using calcium imaging and multi-electrode arrays was assessed for the first time. RIPK1 blockade was shown to partially preserve both calcium and bioelectric activity of neuron-glial networks under ischemic factors. However, it should be noted that RIPK1 blockade does not preserve the network parameters of the collective calcium dynamics of neuron-glial networks, despite the maintenance of network bioelectrical activity (the number of bursts and the number of spikes in the bursts). To confirm the data obtained in vitro, we studied the effect of RIPK1 blockade on the resistance of small laboratory animals to in vivo modeling of hypoxia and cerebral ischemia. The use of Necrostatin-1 increases the survival rate of C57BL mice in modeling both acute hypobaric hypoxia and ischemic brain damage.     

Pattern of the atom ordering in a melt and surface properties of systems with intermetallic compounds

A local atomic structure of the Ni-Al, Ni-Ge, and Ni-Sn melts has been analyzed using the models reconstructed from experimental curves of the structure factor employing the reverse Monte Carlo and Voronoy-Delaunay methods. It has been found that a decisive effect on the formation of the short-range structure, type of the atomic interaction, and surface properties of melts of systems with intermetallic compounds is exerted by the retention of the component interaction intensity and the chemical bond type in melting intermetallic phases, which causes the correlation between the structures of the liquid and solid phases. A change in the pattern of the atom ordering in melts (an intensification of the interaction between like atoms, while the interaction between unlike atoms weakens in the Ni-Al → Ni-Ge → Ni-Sn order) results in the change of thermodynamic and surface properties of melts.     

The nature of the ordering of atoms in a melt and the surface properties of simple eutectic systems

Using the models reconstructed from the experimental structure factor curves by the reverse Monte-Carlo and Voronoy-Delaunay methods the local atomic structures of the Sn-Ge, Ag-Ge, and Ni-C simple eutectic systems has been analyzed. It has been found that the nature of the atom ordering in melts is responsible not only for the melt bulk properties, but for its surface properties (surface tension, wetting) as well. Clusters that form from atoms of the same sort in melts and whose binding energy inside the clusters exceeds the binding energy between the atoms of a solvent and a cluster, exhibit the surface activity in the melt, which explains the extremes in isotherms of the density and surface tension of the melts. Clusters with a chemical ordering of atoms patterned after the Me₃C electronic compound revealed in the Ni-C and Ag-Ge systems indicate that the equilibrium phase diagrams of these systems at high pressures transform from diagrams of a simple eutectic type to diagrams with a compound, i.e. an increase in pressure contributes to the metallization of bonds in a melt.     

Influence of Heat Treatment on the Mechanical Characteristics of Diamond Powders

Powder Metallurgy and Metal Ceramics - Improvement in the efficiency of diamond tools is inextricably linked with the use of high-strength heat-resistant diamond grains for tooling. Hence, study of...     

Rated power of conscripts in the north

The nutrition on alimentary and power value in the term active duty soldier on the North on norm No 1 (troop ration) approaches to calculated sizes (with the exception of fat deficiency) that allows to support the physical working capacity and the body mass index on high enough level. However insufficient content of vitamins (polyhypovitaminosis) in organisms of most of studied persons was revealed. The dynamics of change of nutrition status in the soldiers on the North during year shows essential dependence on the weather rigidity parameters and the seasonal factor.     

Microstructural Study of Periclase Powders for Production of Periclase-Carbon Components

Results of a microstructure analysis of periclase powders (from China) of fractions 3 – 1 mm are reported. In the production of refractory materials for the lining of steel ladles, preference should be given to fused periclase powders.