Emergence of room-temperature ferroelectricity at reduced dimensions.

The enhancement of the functional properties of materials at reduced dimensions is crucial for continuous advancements in nanoelectronic applications. Here, we report that the scale reduction leads to the emergence of an important functional property, ferroelectricity, challenging the long-standing notion that ferroelectricity is inevitably suppressed at the scale of a few nanometers. A combination of theoretical calculations, electrical measurements, and structural analyses provides evidence of room-temperature ferroelectricity in strain-free epitaxial nanometer-thick films of otherwise nonferroelectric strontium titanate (SrTiO3). We show that electrically induced alignment of naturally existing polar nanoregions is responsible for the appearance of a stable net ferroelectric polarization in these films. This finding can be useful for the development of low-dimensional material systems with enhanced functional properties relevant to emerging nanoelectronic devices.

[Metabolic and organ protective properties of various infusion solutions and the choice of starting therapy in the pre-admission stage of acetic acid poisoning].

MATERIALS AND METHODS: We conducted an open prospective study in 60 patients (30 men and 30 women) with acetic acid poisoning. A randomization was performed on the groups, taking into account the tactics of infusion therapy: group I--15 patients who did not receive an infusion therapy at a pre-admission stage; group II--15 patients who received the infiusion therapy with solution of sodium chloride 0.9%; group III--15 patients who received the infusion therapy with modified gelatin (Gelofusinwn), group IV-15 patients who received the infusion therapy with reamberinum. RESULTS: We found that the most favorable results were noted in patients of group IV in the early posttraumatic period.

[Cholinesterase activity in tissues of some crab species from the Japan Sea].

The comparative study of the cholinesterase activity in some crab species was carried out for the first time with use of a set of thiocholine substrates. The substrate specificity was studied in stellar nerve, heart, and hemolymph of three crab species. The crab hemolymph was shown to be characterized by the highest enzyme activity. The enzyme from various crab organs has different structure o substrate specificity. Properties of crab enzymes was compared with acetylcholinesterase (AChE) of human blood erythrocytes, butyrylcholinesterase (BuChE) of horse blood serum, enzyme o squids and bivalve molluscs. The obtained data allow the conclusion to be made on differences in properties of enzymes both at the interspecies and at the tissue levels.

[A case of beneficial outcome of acute poisoning with potentially lethal doses of paracetamol].

A case of severe paracetamol poisoning is described. The beneficial outcome of potentially fatal poisoning (a single intake of 20 g paracetamol) is believed to depend on intensive therapy with remaxol to maintain reparative processes in hepatocytes.

Ferroelectric polymer gates for non-volatile field effect control of ferromagnetism in (Ga, Mn)As layers.

(Ga, Mn)As and other diluted magnetic semiconductors (DMS) attract a great deal of attention for potential spintronic applications because of the possibility of controlling the magnetic properties via electrical gating. Integration of a ferroelectric gate on the DMS channel adds to the system a non-volatile memory functionality and permits nanopatterning via the polarization domain engineering. This topical review is focused on the multiferroic system, where the ferromagnetism in the (Ga, Mn)As DMS channel is controlled by the non-volatile field effect of the spontaneous polarization. Use of ferroelectric polymer gates in such heterostructures offers a viable alternative to the traditional oxide ferroelectrics generally incompatible with DMS. Here we review the proof-of-concept experiments demonstrating the ferroelectric control of ferromagnetism, analyze the performance issues of the ferroelectric gates and discuss prospects for further development of the ferroelectric/DMS heterostructures toward the multiferroic field effect transistor.

[Brain cholinesterases in marine mammals].

Substrate properties of brain cholinesterases were studied in ringed seal and beluga. Kinetic parameters of hydrolysis of thiocholine esters of carboxylic acids were determined. According to the substrate specificity, the enzyme from the brain of marine mammals can be assigned to acetylcholinesterases. Specific properties of the enzyme from the brain of marine mammals were demonstrated in comparison with land animals. The revealed differences in kinetic parameters of the brain enzyme activity are considered in terms of different biochemical adaptation in ringed seal and beluga.

[Substrate specificity of brain cholinesterase activity of evolutionary old species of fishes]. / Substratnaia spetsifichnost' kholinésteraznoi aktivnosti tkani mozga évoliutsionno drevnikh vidov ryb.

An analysis of brain cholinesterase properties in 3 species of cartilaginous fishes and 1 species of chondrostei, was conducted for the first time. The skates brain enzymes, as to substrate specificity, are shown to be referred to acetylcholinesterases, and the shark brain cholinesterase - to atypical acetylcholinesterase. Kaluga brain cholinesterase, as to its substrate specificity, differes from brain enzymes of cartilaginous fishes. The differences in properties of the nervous tissue cholinestarase of the investigated fish species are the parameters of evolutionary divergence of species.