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The reaction of 1-vinyl-4,5-dihydro-1H-benzo[g]indole with C-aryl-N-methylnitrones in the presence of nickel (II) perchlorate proceeds regioselectively to form a mixture of diastereomeric adducts of formal (3+3) cycloaddition, whereas the main products of the reaction with C,N-diarylnitrones are dipyrromethanes. [ABSTRACT FROM AUTHOR]

The symposium on the chemistry of alkynes, allenes, and small rings was held on July 3–6, 2023 at St. Petersburg State University as part of the All-Russian conference with international participation "Ideas and Legacy of A.E. Favorsky in Organic Chemistry." Leading experts in the chemistry of alkynes, allenes, and small rings took part in the conference, recent advances in the chemistry of compounds of these classes were presented, and prospects for further development of this research field were discussed. Brief annotations of the reports made and references to the relevant publications of the authors are collected in the present review. [ABSTRACT FROM AUTHOR]

New 5-ethynylisoxazoles were obtained via 1,3-dipolar cycloaddition reactions of nitrile oxides with buta-1,3-diynes. The cycloaddition proceeds regioselectively by the terminal triple bond. [ABSTRACT FROM AUTHOR]

The VIth International Symposium "The Chemistry of Diazo Compounds and Related Systems" (DIAZO 2021) was held at the St. Petersburg State University from 6 to 10 September 2021. At the symposium, the advances in diazo chemistry over the past decade were summed up, and promising directions for further research were discussed. The review contains brief annotations of the plenary, keynote, invited and oral presentations and includes references to the relevant works of the speakers. [ABSTRACT FROM AUTHOR]

Magnetite-gold hybrid magnetic nanoparticles of the dumbbell type were used to immobilize two proteins: α-chymotrypsin and the Bowman–Birk inhibitor. It is shown that under the influence of a low-frequency magnetic field (50 Hz), the activity of chymotrypsin bound in a complex with an inhibitor is drastically reduced depending on the magnetic field induction. We hypothesize that this effect is related to the aggregation of magnetic nanoparticles under the influence of a magnetic field. [ABSTRACT FROM AUTHOR]

Liver cirrhosis is a major cause of death worldwide and is characterized by extensive fibrosis. There are currently no effective antifibrotic therapies available. To obtain a better understanding of the cellular and molecular mechanisms involved in disease pathogenesis and enable the discovery of therapeutic targets, here we profile the transcriptomes of more than 100,000 single human cells, yielding molecular definitions for non-parenchymal cell types that are found in healthy and cirrhotic human liver. We identify a scar-associated TREM2+CD9+ subpopulation of macrophages, which expands in liver fibrosis, differentiates from circulating monocytes and is pro-fibrogenic. We also define ACKR1+ and PLVAP+ endothelial cells that expand in cirrhosis, are topographically restricted to the fibrotic niche and enhance the transmigration of leucocytes. Multi-lineage modelling of ligand and receptor interactions between the scar-associated macrophages, endothelial cells and PDGFRα+ collagen-producing mesenchymal cells reveals intra-scar activity of several pro-fibrogenic pathways including TNFRSF12A, PDGFR and NOTCH signalling. Our work dissects unanticipated aspects of the cellular and molecular basis of human organ fibrosis at a single-cell level, and provides a conceptual framework for the discovery of rational therapeutic targets in liver cirrhosis. Single-cell RNA sequencing is used to characterize and compare the functional diversity of cells from liver biopsies of human scarred and normal liver, and identifies markers for scar-associated macrophages and endothelial cells. [ABSTRACT FROM AUTHOR]

Abstract—The paper considers theoretical and practical problems on developing electron-optical systems of traveling wave tubes (TWTs) that focus an intense electron flow via a magnetic periodic focusing system (MPFS) upon advancement into the millimeter-wave range. An analytical solution has been found for the magnetic field distribution in an MPFS TWT combined with a retarding system with magnetically soft inserts that form a passage channel with a diameter substantially less than the internal diameter of the tip. The stable focusing zones of the electron flow are determined for the considered MPFS, which makes it possible to focusing the flow with magnetic field parameters exceeding the critical values of a conventional MPFS. [ABSTRACT FROM AUTHOR]

We demonstrated the possibility of penetration of magnetite-gold nanoparticles conjugated with prostate-specific membrane antigen into mouse macrophages. It was found that after 3-h incubation with nanoparticles in a concentration of 15 mg/liter at 37oC, they were seen in only 13% macrophages. In about 90% cells, the nanoparticles were detected within the cytoplasm. Under these conditions, membrane damage was revealed in 25% cells. These results should be taken into account in further development and application of nanomaterials for diagnostic and therapeutic purposes in oncology. [ABSTRACT FROM AUTHOR]

An innovative nanomechanical strategy for in vivo biomedical applications is reviewed. The strategy is based on the use of complexes of special functionalized magnetic nanoparticles controlled by an external low-frequency nonheating magnetic field as deformation machines. The advantages of the strategy are the possibility of easily achieved nanoscale locality and molecular selectivity of action (at the level of individual macromolecules and macromolecular structures such as liposomes, living cells, cell organelles), multimodality, safety, and a high potential of therapeutic application, in particular, for noninvasive oncotherapy without drugs. [ABSTRACT FROM AUTHOR]

Functionalized magnetic nanoparticles (MNPs) controlled by an external magnetic field provide a new generation of promising nanobiomedical platform. Due to their ability to locally change the state of a biochemical system through two physical processes—thermal and nanomagnetomechanical—they are already used in experiments on targeted drug delivery and therapy of oncological diseases. This work considers the peculiarities, advantages, and drawbacks of each of these processes and the main parameters of the magnetic field controlling the MNP effect on different biomolecular targets. A brief review and comparative analysis of main experimental studies carried out in the scope of magnetic hyperthermia and nanomagnetomechanical actuation are carried out. [ABSTRACT FROM AUTHOR]

In this work, a novel approach to magnetic nanotheranostics based on the activation of magnetic nanoparticles (MNPs) with a nonheating low-frequency magnetic field has been described. Electromagnetic biomedical technologies implemented in low-frequency nonheating and radiofrequency heating magnetic fields have been briefly reviewed and compared. It has been shown that the activation of MNPs with nonheating magnetic fields has several advantages over activation with heating magnetic fields, namely, a more universal character and penetration ability into tissues, easy dosage and control, higher locality and safety, molecular selectivity, and lower cost. A combination of methods developed and patented by us can form a technological platform for new-generation low-frequency magnetic theranostics which is significantly more effective and possesses more options than conventional radiofrequency theranostics. [ABSTRACT FROM AUTHOR]

Thermal addition of aldonitrones (C,N-diaryl- and N-aryl-C-arylcarbamoylnitrones) to the double bond of N-phenyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboximide yields heteropropellanes containing isoxazolidine and pyrrolidine fragments. The cycloaddition of C,N-diarylnitrones is stereoselective, and only one diastereoisomer is formed. [ABSTRACT FROM AUTHOR]

1,3-Dipolar cycloaddition of nitrile oxides and nitrones to N-vinylindole proceeds regioselectively at the exocyclic multiple bond to form 5-indolyl-substituted isoxazolines and isoxazolidines in good yields. [ABSTRACT FROM AUTHOR]

The results of numerical simulation of electrodynamic characteristics of a slow-wave structure shaped as a folded waveguide and an electron-optical system of a three-millimeter-band pulse travelling wave tube with an output pulsed power of up to 50 W are presented. The matching devices, the interaction space, and the electron-optical system are calculated, which allows determination of their constructive parameters. The effect of loss caused by the roughness of the surfaces of the walls of the electrodynamic system on the output characteristics of the device is estimated. [ABSTRACT FROM AUTHOR]

In this work we present the results of the synthesis of magnetite-gold nanoparticles with a core-shell structure. The preparation is carried out in several stages: synthesis of the core, coating with a gold shell, purification of magnetite-gold particles from an uncoated magnetite, and functionalization of the surface with sulfur-containing ligands. The conditions needed for the functionalization of nanoparticles with lipoic acid and mercapto-methoxy polyethylene glycol are indicated in detail, making it possible to determine the optimal conditions needed to achieve an efficient purification and a maximum concentration of the particles in a solution required for biological tests. The possibility of remotely controlling the chymotrypsin properties using an alternating magnetic field has been demonstrated by the example of magnetite-gold nanoparticles. The magnetite-gold nanoparticles which we have obtained are promising for future biomedical applications. [ABSTRACT FROM AUTHOR]

Nitrones cycloaddition to 1-vinyl-4,5-dihydro-1 H-benzo[ g]indole proceeds regio- and steroselectively affording a single diastereomer of 5-(hetaryl-substituted)isoxazolidine. [ABSTRACT FROM AUTHOR]

Results of the numerical simulation of the slow-wave structure and the electron-optical system of a wideband continuous-wave traveling-wave tube with an output power of 250 W and gain of 23 dB, which is designed for operation in an X/Ku-band vacuum solid-state amplifying module, are given. [ABSTRACT FROM AUTHOR]

A new approach to the control of biochemical reactions in magnetic nanosuspensions exposed to a low-frequency (nonheating) magnetic field, which has a nanomechanical effect on macro-molecules chemically linked to magnetic nanoparticles (MNPs), is described. Experimental verification of this approach showed that a magnetic field with an intensity of from 15 to 220 kA/m and a frequency of 50 Hz affected the kinetics of a chemical reaction in an aqueous solution containing suspended MNPs of magnetite (FeO · FeO) and chymotrypsin molecules linked to them through polymer bridges. The field dependence of the effect is shown. The effect is interpreted within the framework of a nanomechanical model taking into account the deformations, conformational change, and destruction of weak bonds in the enzyme macromolecule under the action of the forces applied to it during the orientation of MNPs in the field. [ABSTRACT FROM AUTHOR]

Methodological aspects of drop tests for high-ductility pipe steel are discussed. The basic advantages and disadvantages of various methods of assessing the test results are noted. Recommendations are made for the optimization of the test conditions so as to obtain more objective results. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of the Ln2BaO4 phases (Ln = Dy, Ho, Sm) were studied by the electromotive force method with a fluoride electrolyte (890–1180 K), solution calorimetry in 1.07 N hydrochloric acid at 298.15 K, and differential scanning calorimetry (298–860 K). The experimental data were jointly processed, and the thermodynamic functions of the compounds over the temperature range 298–1200 K were calculated. [ABSTRACT FROM AUTHOR]

The investigation demonstrated that an iron, nickel, and zinc hydroxide mixture of the required composition can be prepared electrolytically. The resultant system can readily be converted into an oxide mixture and used for ferrite manufacture. By using hydrochloric acid solutions as electrolytes, it is possible to deposit hydroxide mixtures of high purity and to eliminate washing, which is time consuming and requires a large quantity of distilled water. In contrast to the usual chemical method of hydroxide preparation, the electrochemical method makes it possible to produce, in a single, continuous technological process, a thoroughly blended oxide mixture of high purity and adequate homogeneity and to eliminate the time-consuming and laborious operation of mechanical mixing and comminution of starting oxide powders. [ABSTRACT FROM AUTHOR]

An increased reactivity of esters of acetylmethyl- and carboxymethylphosphonic acids in a spontaneous hydrolysis and of esters of acetylalkylphosphonic acids in alkaline hydrolysis as the result of intramolecular catalysis has been established. Enol forms of the esters participate in the mechanisms of the intramolecular catalysis. [ABSTRACT FROM AUTHOR]

A study was made of the kinetics of the alkaline hydrolysis of some phenyl esters of phosphorus acids. An estimate was made of the contribution made by the induction effect and the p−d conjugation of the phenoxyl group to the free activation energy of the alkaline hydrolysis of the investigated esters. [ABSTRACT FROM AUTHOR]

The kinetics of the hydrolysis of bis (chloromethyl)phosphinic esters was investigated in KOH medium at 10 and 25°. The rate constants are correlated with the steric constants of the leaving groups. [ABSTRACT FROM AUTHOR]

A study was made of the hydrolysis kinetics of some esters of bis(chloromethyl)phosphinic acid in water at 75-95°. The reaction rate depends on the nature of the alcohol radical, and for the alkyl radicals is determined by the steric factor. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common sustained arrhythmia and carries an increased risk of stroke and heart failure. Here we investigated how the immune infiltrate of human epicardial adipose tissue (EAT), which directly overlies the myocardium, contributes to AF. Flow cytometry analysis revealed an enrichment of tissue-resident memory T (T RM ) cells in patients with AF. Cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) and single-cell T cell receptor (TCR) sequencing identified two transcriptionally distinct CD8 + T RM cells that are modulated in AF. Spatial transcriptomic analysis of EAT and atrial tissue identified the border region between the tissues to be a region of intense inflammatory and fibrotic activity, and the addition of T RM populations to atrial cardiomyocytes demonstrated their ability to differentially alter calcium flux as well as activate inflammatory and apoptotic signaling pathways. This study identified EAT as a reservoir of T RM cells that can directly modulate vulnerability to cardiac arrhythmia., (© 2024. The Author(s).)