An original method has been developed for the synthesis of 1,3-dyine derivatives of natural lembehyne B in high yields (50–67%) and with high selectivity (>98%). The key stage of the synthesis is new ...Ti-catalyzed cross-cyclomagnesiation of oxygenated and aliphatic 1,2-dienes induced by Grignard reagents. For studying the effect of the structure on the antitumor and neuritogenic activities, a series of lembehyne B analogues with different distances between the terminal hydroxy group and the 1,3-diyne moiety was prepared and tested for neuritogenic activity on mouse neuroblastoma Neuro 2A cells and for cytotoxicity, induction of apoptosis, and effects on the cell cycle using Jurkat, U937, K562, HeLa, and Hek293 tumor cell lines.
The effect of the nitriding temperature in electron beam plasma on the structural and phase composition of the surface layers of metastable austenitic stainless steels is studied. Conversion electron ...Mössbauer spectroscopy shows that nitriding at 350°C results in the transition of the austenite into the α (bcc) phase by the shear mechanism in the surface layers of a plate (tenths of a micron). A nitrogen supersaturated austenite and a mixture of nitrides with a predominant configuration of three nitrogen atoms in the environment of iron are formed in layers 1–5 μm thick. Nitriding at a temperature of 500°C and above leads to nitrogen supersaturated austenite decomposition, the escape of chromium and nitrogen from the matrix into nitrides CrN, Fe
4
N, and Fe
x
N, and the subsequent γ → α phase transformation.
Ribonuclease from Bacillus intermedius (binase) is a small basic protein with antitumour activity. The three‐dimensional structure of the binase mutant form Glu43Ala/Phe81Ala was determined at 1.98 Å ...resolution and its functional properties, such as the kinetic parameters characterizing the hydrolysis of polyinosinic acid and cytotoxicity towards Kasumi‐1 cells, were investigated. In all crystal structures of binase studied previously the characteristic dimer is present, with the active site of one subunit being blocked owing to interactions within the dimer. In contrast to this, the new mutant form is not dimeric in the crystal. The catalytic efficiency of the mutant form is increased 1.7‐fold and its cytotoxic properties are enhanced compared with the wild‐type enzyme.
This article presents the results of studies that the authors conducted proceeding from a hypothesis that an increase of crises phenomena in the global economy, uncertainty, and higher risk along ...with the growing use of digital smart technology apply radically new requirements on knowledge-intensive services in the energy sector. The sector of management consulting and engineering services, which constitute the backbone of knowledge-intensive services, is faced with a new role of providing a mix of services addressing the tasks of devising anticipatory actions amid uncertainty and crisis based on forecasting. Analysis of changes in business models and the content of services indicate their strong capacity for smart logistics of complex projects, knowledge transfer in cooperation with universities and innovation institutions, managing the development of flexible technological and product solutions, and competency development in network teams. This article offers a detailed elaboration of an up-to-date conceptual framework of engineering and management consulting; provides an overview of global trends; and presents a case study of collaboration problems that emerge in cross-disciplinary teams working on smart grid projects and projects of energy supply in cities based on smart grid technology. A model of proactive management and anticipatory personnel training in energy companies is proposed. This article describes the skillset needed for implementing a concept of integrated knowledge-intensive services for technological modernization and digitalization of the energy sector.
Sodium-potassium adenosine triphosphatase (Na,K-ATPase) creates a gradient of sodium and potassium ions necessary for the viability of animal cells, and it is extremely sensitive to intracellular ...redox status. Earlier we found that regulatory glutathionylation determines Na,K-ATPase redox sensitivity but the role of basal glutathionylation and other redox modifications of cysteine residues is not clear. The purpose of this study was to detect oxidized, nitrosylated, or glutathionylated cysteine residues in Na,K-ATPase, evaluate the possibility of removing these modifications and assess their influence on the enzyme activity. To this aim, we have detected such modifications in the Na,K-ATPase α1-subunit purified from duck salt glands and tried to eliminate them by chemical reducing agents and the glutaredoxin1/glutathione reductase enzyme system. Detection of cysteine modifications was performed using mass spectrometry and Western blot analysis. We have found that purified Na,K-ATPase α1-subunit contains glutathionylated, nitrosylated, and oxidized cysteines. Chemical reducing agents partially eliminate these modifications that leads to the slight increase of the enzyme activity. Enzyme system glutaredoxin/glutathione reductase, unlike chemical reducing agents, produces significant increase of the enzyme activity. At the same time, the enzyme system deglutathionylates native Na,K-ATPase to a lesser degree than chemical reducing agents. This suggests that the enzymatic reducing system glutaredoxin/glutathione reductase specifically affects glutathionylation of the regulatory cysteine residues of Na,K-ATPase α1-subunit.
In this work, a combination of small-angle neutron scattering, dynamic light scattering and rheometry was applied in order to investigate the structure and oil responsiveness of anionic/cationic ...wormlike surfactant micelles formed in a mixture of potassium oleate and n-octyltrimethylammonium bromide (C8TAB). A new facile method of calculating the structure factor of charged interacting wormlike micelles was proposed. It was shown that the mean distance between the micelles decreases upon the increase of the amount of cationic co-surfactant and lowering of the net micellar charge. It was demonstrated that highly viscous fluids containing mixed anionic/cationic wormlike micelles are highly responsive to oil due to its solubilization inside the micellar cores, which leads to the disruption of micelles and formation of microemulsion droplets. Experimental data suggest that solubilization of oil proceeds differently in the case of mixed anionic/cationic micelles in the absence of salt, and anionic micelles of the same surfactant in the presence of KCl.
A pulsed source of ions with ionization of the substance under study at atmospheric pressure by the UV radiation of laser plasma is numerically simulated. The calculations are based on an original ...mathematical model that describes evolution of an ensemble of ions in the presence of superimposed gas-dynamic and electric fields with allowance for the Coulomb interaction. The model contains a system of the Navier–Stokes equations for gas-dynamic flows in the volume under study, the Poisson equation for the resulting distribution of electric field in such a volume, and the Lorentz equation for construction of ion trajectories from the ionization place to collecting diaphragm. Convergence of the relaxation method is demonstrated for the numerical solution of the main model equations. The dependence of ion current on applied voltage is studied. It is shown that the calculated results are in good agreement with the experimental data when finiteness of the ion lifetime due to recombination effect is taken into account.
The structural and magnetic properties of thin-film Fe/poly(diphenylene phthalide) (PDP)/Fe systems are studied, along with the behavior of these systems in magnetic fields. The mean surface ...roughness of the studied samples is around 5–8 nm, and local near-surface magnetic properties show variation within 10%. The samples are characterized by two-step hysteresis loops, the step size depending on the thickness of the polymer layer and the difference in the thickness between the magnetic layers. The results are explained by the effects the exchange interaction between the magnetic layers, mediated by the PDP interlayer, has on the behavior of our samples in a magnetic field.
This study reports the effects of the iron chelator deferoxamine (DFO) on collagen cleavage, inflammation, and chondrocyte hypertrophy in relation to energy metabolism-related gene expression in ...osteoarthritic (OA) articular cartilage. Full-depth explants of human OA knee articular cartilage from arthroplasty were cultured with exogenous DFO (1–50 μM). Type II collagen cleavage and phospho-adenosine monophosphate-activated protein kinase (pAMPK) concentrations were measured using ELISAs. Gene expression studies employed real-time PCR and included AMPK analyses in PBMCs. In OA explants collagen cleavage was frequently downregulated by 10–50 μM DFO. PCR analysis of 7 OA patient cartilages revealed that 10 μM DFO suppressed expression of MMP-1, MMP-13, IL-1β, and TNFα and a marker of chondrocyte hypertrophy, COL10A1. No changes were observed in the expression of glycolysis-related genes. In contrast, expressions of genes associated with the mitochondrial Krebs cycle (TCA), AMPK, HIF1α, and COL2A1 were upregulated. AMPK gene expression was reduced in OA cartilage and increased in PBMCs from the same patients compared to healthy controls. Our studies demonstrate that DFO is capable of suppressing excessive collagenase-mediated type II collagen cleavage in OA cartilage and reversing phenotypic changes. The concomitant upregulation of proanabolic TCA-related gene expressions points to a potential for availability of energy generating substrates required for matrix repair by end-stage OA chondrocytes. This might normally be prevented by high whole-body energy requirements indicated by elevated AMPK expression in PBMCs of OA patients.
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