Layer-selective magnetization switching in the chirped photonic crystal with GdFeCo.

Here we propose a magnetophotonic structure for the layer-selective magnetization switching with femtosecond laser pulses of different wavelengths. It is based on a chirped magnetophotonic crystal (MPC) containing magnetic GdFeCo and nonmagnetic dielectric layers. At each operating wavelength the laser pulses heat up to necessary level only one GdFeCo layer that leads to its magnetization reversal without any impact on the magnetization of the other layers. Moreover, magneto-optical reading of the MPC magnetization state is discussed. Lateral dimensions of the considered MPC can be made small enough to operate as a unit cell for data storage.

Experimental study of homogeneous nucleation from the bismuth supersaturated vapor: evaluation of the surface tension of critical nucleus.

The homogeneous nucleation of bismuth supersaturated vapor is studied in a laminar flow quartz tube nucleation chamber. The concentration, size, and morphology of outcoming aerosol particles are analyzed by a transmission electron microscope (TEM) and an automatic diffusion battery (ADB). The wall deposit morphology is studied by scanning electron microscopy. The rate of wall deposition is measured by the light absorption technique and direct weighting of the wall deposits. The confines of the nucleation region are determined in the "supersaturation cut-off" measurements inserting a metal grid into the nucleation zone and monitoring the outlet aerosol concentration response. Using the above experimental techniques, the nucleation rate, supersaturation, and nucleation temperature are measured. The surface tension of the critical nucleus and the radius of the surface of tension are determined from the measured nucleation parameters. To this aim an analytical formula for the nucleation rate is used, derived from author's previous papers based on the Gibbs formula for the work of formation of critical nucleus and the translation-rotation correction. A more accurate approach is also applied to determine the surface tension of critical drop from the experimentally measured bismuth mass flow, temperature profiles, ADB, and TEM data solving an inverse problem by numerical simulation. The simulation of the vapor to particles conversion is carried out in the framework of the explicit finite difference scheme accounting the nucleation, vapor to particles and vapor to wall deposition, and particle to wall deposition, coagulation. The nucleation rate is determined from simulations to be in the range of 10(9)-10(11) cm(-3) s(-1) for the supersaturation of Bi(2) dimers being 10(17)-10(7) and the nucleation temperature 330-570 K, respectively. The surface tension σ(S) of the bismuth critical nucleus is found to be in the range of 455-487 mN/m for the radius of the surface of tension from 0.36 to 0.48 nm. The function σ(S) changes weakly with the radius of critical nucleus. The value of σ(S) is from 14% to 24% higher than the surface tension of a flat surface.

Vortex twins and anti-twins supported by multiring gain landscapes.

We address the properties of multivortex soliton complexes supported by multiring gain landscapes in focusing Kerr nonlinear media with strong two-photon absorption. Stable complexes incorporating two, three, or four vortices featuring opposite or identical topological charges are shown to exist. In the simplest geometries with two amplifying rings vortex twins with equal topological charges exhibit asymmetric intensity distributions, while vortex anti-twins may be symmetric or asymmetric, depending on the gain level and separation between rings.

[Comparison of lipid metabolism in rat liver cells and nuclei during cycloheximide-induced superinduction of nuclear oncogenes]. / Sravnenie metabolizma lipidov v iadrakh i kletkakh pecheni krys v usloviiakh TsGI-indutsirovannoi superékspressii iadernykh onkogenov.

Using a model of cycloheximide (CHI)-induced expression of nuclear oncogens, a comparative study of metabolism of the major lipid classes in rat liver nuclei and cells was carried out. A short-term activation of sphingomyelinase which preceded on a time scale the maximal accumulation of c-fos and c-myc transcripts was observed both in the cells and in the nuclei. In contrast with the whole cell, the level of phospholipase C activity in the nuclei did not change under conditions of oncogene activation. It was found that the maximal expression of nuclear oncogens coincided in time with cyclic changes in the content of practically all phospholipids and neutral lipids with simultaneous activation of their synthesis both in the cells and in the nuclei. However, in the nuclei the sphingomyelin metabolism activation was predominant. It is concluded that in the nucleus sphingomyelin and its metabolites may influence oncogene expression via nuclear protein kinase C.

[Study of sphingomyelinase activity and sphingomyelin and ceramide levels in comparison with other lipid fractions of the cell nucleus in regenerating rat liver]. / Izuchenie urovniia aktivnosti sfingomielinazy i soderzhaniia sfingomielina i tseramidov v sravnenii s drugimi fraktsiiami lipidov kletochnogo iadra regeneriruiushchei pecheni krys.

The changes in the activity of cell nuclear sphingomyelinase at different times of activation of RNA and DNA syntheses in regenerating rat liver were studied. A comparative analysis of the intranuclear content of sphingomyelin and the primary product of the sphingomyelinase reaction, ceramide, as well as of other classes of phospholipids and neutral lipids, was carried out. The changes in the sphingomyelin and ceramide content in the nuclei during the induction of synthetic processes were more conspicuous as compared with other phospholipid classes. Neutral lipids of cell nuclei were also shown to undergo substantial changes. The mechanism of possible involvement of sphingomyelin and other lipids in the regulation of replication and transcription processes is discussed.