Spin-glass polyamorphism induced by a magnetic field in LaMnO single crystal.

We present experimental evidence of field-driven transition in spin-glass state, similar to pressure-induced transition between amorphous phases in structural and metallic glasses, attributed to the polyamorphism phenomena. Cusp in temperature dependences of ac magnetic susceptibility of weakly disordered LaMnO single crystal is registered below the temperature of magnetic ordering. Frequency dependence of the cusp temperature proves its spin-glass origin.

AC response of 2H-NbSe2 single crystals with electron-irradiation-induced defects.

The generation of defects in NbSe(2) single crystals by electron irradiation has been investigated by a combination of ac susceptibility and structural measurements. Remarkably, thanks to the layered structure of NbSe(2), we show that electronic irradiation cannot only create point defects but also in-plane extended defects, which modify anisotropically the ac response. Indeed, the analysis of the onset of the nonlinear susceptibility response, H(ac)(l)(T), as a function of irradiation dose and field orientation shows a correlated increase in the density of anisotropic defects induced by electron irradiation.

(93)Nb NMR study of the charge density wave state in NbSe(2).

(93)Nb NMR studies were carried out for a single crystal of NbSe(2) at 73.328 MHz in the temperature range 9-300 K to investigate the normal and charge density wave (CDW) states. Detailed analysis of the NMR line shape of the central transition using a classical incommensurate model reveals the change in the conduction electron spin dynamics from above T(CDW).

[Pleiotrophic effects of the bl gene and its practical value for selection in tomatoes].

Being of great value for creation of one-stem forms of tomato, the gene bl manifests a number of pleiotropic effects, which complicate its practical usage. There is shown that the gene manifestation depends significantly on the influence of the environment and the genetic background. Sometimes it is possible to avoid the manifestation of undesirable gene effects by creation of the favorable genetic surroundings.

Stripe conductivity in La1.775Sr0.225NiO4.

We report Raman light-scattering and optical conductivity measurements on a single crystal of La1.775Sr0.225NiO4 which exhibits incommensurate charge-stripe order.

Investigation of the structural phase transitions near 190 K in 4,4'-dichlorobenzophenone.

X-ray structure studies have been carried out on single crystals of 4,4'-dichlorobenzophenone at temperatures from 164 to 295 K. The structure determined at 164 K is monoclinic I2/c. Crystal data: T = 164 K; a = 24.

[Thymidine phosphorylation with the participation of rat thymic and hepatic thymidine kinase in the presence of a factor from Cl. perfringens (welchii)].

Factor CPW, isolated from Cl. perfringens/welchii was shown to activate latent thymidine kinase (factor N) from liver tissue of rats beginning from 42 days age. CPW factor activated 3.

[Regulation of asparaginase and glutaminase activity in Pseudomonas fluorescens mutants lacking in the ability to synthesize glutamic acid].

A mutant of Pseudomonas fluorescens, AG-M49, has been isolated, which lacks the ability to synthesize glutamic acid. The mutant contains both aspartase A and aspartase AG. The mutant was characterized by a considerably high activity of glutaminase and aspartase, increasing with the rate flow, during its continuous cultivation on a medium with L-glutamate.

[Regulation of L-asparaginase biosynthesis in mutants of Bacillus mesentericus 43A, poorly growing in the presence of aspartic acid].

Biosynthesis of L-asparaginase (EC 3.5.1.

[Amino acid regulation of L-asparaginase formation in Bacillus mesentericus].

The role of amino acids in regulation of L-asparaginase formation was studied in Bacillus mesentericus 43A. Asparagic acid and, to a less extent, asparagine repress biosynthesis of the enzyme. Glutamic acid, glutamine, and other 15 studied amino acids, added separately at a concentration of 10 or 20 mM to the growing culture, have no effect on the activity of the enzyme.

[Asparaginase and glutaminase activity in Pseudomonas fluorescens in continuous cultivation].

The cells of Pseudomonas fluorescens AG contain two inducable asparaginase enzymes: one of them hydrolyzes only L-asparagine (asparaginase A), the other--L-asparagine, L-glutamine, and D-asparagine (asparaginase AG). In the conditions of continuous cultivation of the bacteria, aspartic and glutamic acids induce the formation of these enzymes only when the amino acids were used simultaneously as a growth-limiting factor and as a sole source of carbon and nitrogen. Both enzymes are not induced in the conditions when the growth is limited by the nitrogen of these amino acids.