Arginine-hydrolyzing enzymes for electrochemical biosensors

Since l-Arginine (Arg) is a semi-essential amino acid for humans, its adequate amount must be consumed in the diet to prevent certain negative consequences related to insufficient synthesis of this amino acid under specific physiological conditions. Arg metabolism results in the production of a biochemically diverse range of such products as urea, some amino acids, creatine, polyamines, nitric oxide, etc. Arg, an important biomarker in clinical diagnostics, is also used for prevention/treatment of different diseases, including cancer and COVID-19. Furthermore, it serves as an indicator of food and beverages quality.A variety of optic and electrochemical methods for Arg determination have already been suggested. The biosensor systems based on the enzymes of Arg metabolism were shown to be the most promising tools for Arg assay. This review focuses on the peculiarities of electrochemical biosensors for Arg assay based on the use of Arg-degrading enzymes and on the analysis of their advantages as compared to other approaches.     

Orbital Ordering Effect on Magnetic Resonance Spectra in Charge-Ordered and Frustrated Manganites

Physics of the Solid State - A theoretical study of the interrelation of the crystal structure, charge, orbital, and magnetic subsystems in R1 – xAxMnO3 charge-ordered...     

Convex hyperspaces of probability measures and extensors in the asymptotic category

The objects of the Dranishnikov asymptotic category are proper metric spaces and the morphisms are asymptotically Lipschitz maps. In this paper we provide an example of an asymptotically zero-dimensional space (in the sense of Gromov) whose space of compact convex subsets of probability measures is not an absolute extensor in the asymptotic category in the sense of Dranishnikov.     

Synthesis of new-type 1,3,6-triazocine via intramolecular reactions of iodocyclization and [3+2] azido cycloaddition

Selective iodocyclization of 6-(alkenylamino)-1-allylpyrazolo[3,4-d]pyrimidines provided hydrogenated derivatives of 1-allyl-8(9)-iodomethylimidazo(pyrimido)[1,2-a]pyrazolo[4,3-e]pyrimidines which were further reacted with NaN₃ at 75°С to 80°С to give a series of new-type 1,3,6-triazocines annulated with the pyrazole, pyrimidine, imidazole (or pyrimidine), and 1,2,3-triazole rings. The compounds synthesized were structurally characterized by analytical, spectral (IR, ¹H and ¹³C NMR, HPLC-mass), and X-ray diffraction data.     

Sulfanyl chloride induced heterocyclization of N-(pyrazolyl)styrylacetamides

Heterocyclization of N-(pyrazol-3-yl)styrylacetamides with arenesulfenyl chlorides yields the corresponding tetrahydrofuran-2-iminium perchlorates isolable after chromatography as trans-5-aryl-4-(arylthio)tetrahydrofuran-2-ones and 5-aryl-4-(arylthio)-1-(pyrazol-3-yl)pyrrolidin-2-ones, with the latter predominating. N-(Pyrazol-4-yl)styrylacetamides react under analogous conditions to give 5-aryl-4-(arylthio)-1-(pyrazol-4-yl)pyrrolidin-2-ones, 4-aryl-3-(arylthio)-4-chloro-N-(1-methylpyrazol-4-yl)butanamides, and tetrahydrofuran-2-iminium perchlorates which, when chromatographed, produce 5-aryl-4-(arylthio)dihydrofuran-2(3H)-ones and 4-aryl-3-(arylthio)-4-methoxy-N-(1-methyl-1H-pyrazol-4-yl)butanamides.     

The dynamical description of the mass distribution of fission fragments

The variances of the mass distribution of fission fragments for nuclei in the fissility parameter range 30 < Z²/A < 40 have been calculated. The Fokker-Planck equation for the distribution function of collective variables is used as a dynamical equation to describe the descent of the fissioning nucleus from the saddle to scission. The calculations reproduce the experimentally observed increase of the mass variances with a growth of the parameter Z²/A. The increase of the calculated variances is due to a considerable decrease in the stiffness coefficients corresponding to the saddle points for heavy fissioning nuclei and to the non-equilibrium character of the descent.     

Phase transitions in adsorbed films of barium on W(011)

Phase transitions in barium submonolayers adsorbed on W(011) are studied in a wide range of temperatures and coverages by the LEED technique, including the temperature measurement of the diffraction intensity. The regions of ordered and disordered structures are determined, the result is presented in the form of phase diagram. The temperature dependence of the adfilm Bragg intensity in the low temperature limit (the lowest temperature is 5 K) shows an appreciable slope for all incoherent and almost all coherent structures, except for (3×2). The fact is discussed in terms of the adfilm long- and quasi-long-range order. The disordering of the (3 × 2) lattice near T_c=130 K is the second-order phase transition with the order parameter critical exponent β=0.16. the adfilm is two-phase in the range n=(3.2?3.8)×10¹⁴cm^?2 and singlehase for the rest of the coverages. The effect of the first-order phase transition on the character of the work function change in the two-phase region is discussed.