The evolution of the nanoscale dissipative structures in a distribution of defects within the isothermally irradiated f.c.c. crystal

A kinetic model for the influence of external noises such as fluctuations of the vacancies’ generation rate and inhomogeneity of irradiated f.c.c. crystal on the formation of nanoscale modulated dissipative structure in a spatial distribution of vacancies is considered. The generation rate of vacancies all over the sites and a density of their dislocation-type sinks are modelled as independent random uniform stationary fields and with certain defined parameters of fluctuation correlations – spatial and temporal ones. Such stochastic fields can induce a spatial redistribution of vacancies that can lead to their density stationary uniform field or stochastic one. By the average value and correlation functions of these fluctuations, the conditions are determined for interacting fluctuations of the vacancies’ density, under which this homogeneous random field becomes unstable in relation to the stochastic field with a spatially periodic mean distribution of vacancies’ density. For instance, with f.c.c. nickel as a model of the irradiated functional material, the temperature dependence of spatial period d(T) of the modulated dissipative structure of vacancies’ subsystem in f.c.c. crystal is numerically forecasted and analysed, taking into account the total (‘electrochemical’?+?‘strain-induced’) interaction between vacancies. Such d(T)-dependence is also determined by the kinetic characteristics of vacancies’ redistribution.     

Synthesis and Biological Activity of Novel Ethyl Esters of 4‐R‐6,8‐Dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic Acids

The novel heterocyclizations of ethyl 5‐(hydrazinocarbonyl)‐2,4‐dimethyl‐1H‐pyrrole‐3‐carboxylate are developed. New derivatives of ethyl esters of 4‐R‐6,8‐dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic acids were obtained. The in vitro anticancer and antibacterial activities of the synthesized compounds were revealed. The most potent antibacterial compound appeared to be 1.3 inhibiting Staphylococcus aureus. Pyrrolo[1,2‐d][1,2,4]triazine 2.15 showed significant antifungal activity against Candida tenuis. The anticancer activity of the synthesized compounds was determined.     

Venom-Derived Neurotoxins Targeting Nicotinic Acetylcholine Receptors

Acetylcholine was the first neurotransmitter described. The receptors targeted by acetylcholine are found within organisms spanning different phyla and position themselves as very attractive targets for predation, as well as for defense. Venoms of snakes within the Elapidae family, as well as those of marine snails within the Conus genus, are particularly rich in proteins and peptides that target nicotinic acetylcholine receptors (nAChRs). Such compounds are invaluable tools for research seeking to understand the structure and function of the cholinergic system. Proteins and peptides of venomous origin targeting nAChR demonstrate high affinity and good selectivity. This review aims at providing an overview of the toxins targeting nAChRs found within venoms of different animals, as well as their activities and the structural determinants important for receptor binding.     

Isotopic Exchange in Porous and Dense Magnesium Borohydride

Magnesium borohydride (Mg(BH₄)₂) is one of the most promising complex hydrides presently studied for energy‐related applications. Many of its properties depend on the stability of the BH₄^? anion. The BH₄^? stability was investigated with respect to H→D exchange. In situ Raman measurements on high‐surface‐area porous Mg(BH₄)₂ in 0.3 MPa D₂ have shown that the isotopic exchange at appreciable rates occurs already at 373 K. This is the lowest exchange temperature observed in stable borohydrides. Gas–solid isotopic exchange follows the BH₄^?+D^.→BH₃D^?+H^. mechanism at least at the initial reaction steps. Ex situ deuteration of porous Mg(BH₄)₂ and its dense‐phase polymorph indicates that the intrinsic porosity of the hydride is the key behind the high isotopic exchange rates. It implies that the solid‐state H(D) diffusion is considerably slower than the gas–solid H→D exchange reaction at the surface and it is a rate‐limiting steps for hydrogen desorption and absorption in Mg(BH₄)_2.     

Pseudo-spherical Submanifolds with Degenerate Bianchi Transformation

We describe pseudo-spherical submanifolds with degenerate Bianchi transformation in constant curvature spaces.     

Investigation of intermolecular interactions in solution polymer‐organic dye by method electronic spectroscopy

It has been shown that specific electrostatic interactions between charges of ion dyes and functional groups of polymer play main role in the cause of polar coulored matrices. These interaction prevent by formation tight ion pairs of dyes and their associates. Therefore, such matrices have practically the same electronic spectra as liquid solution of dyes. Electrostatic interactions between dye counterions dominate in low polarity polymer matrices. Process of formation tight ions pair is became easier. Such pairs cause quenching of the fluorescence and distortion of electronic spectra by comparison with liquids.