Influence of the powders phase composition and sintering atmosphere on the structure and magnetic properties of Mn-Zn ferrites

The magnetic properties of Mn-Zn ferrites depend strongly on the microstructure, chemical and phase composition. In this paper the effect of synthesis and sintering conditions on the structure, phase composition and properties of Mn-Zn ferrites is investigated. The specimens for the study were obtained by pressureless sintering. The magnetic properties were measured on a B-H analyzer. The structure was investigated by XRD and SEM. Materials with an average grain size of 2.2 μm were obtained by sintering at a temperature of 1265 °C. It was found that an increase in the synthesis temperature from 700 to 1000 °C promotes the growth of the initial magnetic permeability of these materials from 1100 to 1370. The rapid cooling of the powders synthesized at 1000 °C allows maintaining a high content of the spinel phase. In the structure of materials obtained by sintering powders with initially high spinel content at 1300 °C, grains of abnormally large size are formed. This leads to an increase in the initial permeability, magnetic induction at Hm = 1200 A/m, f = 10 kHz and magnetic losses at high frequencies (up to 500 kHz). A material with fine-grained structure was obtained by using air at the heating stage of pressureless sintering. This contributed to the reduction of magnetic losses without a significant decrease in Bm

Neutron Age Determination in Fast Reactor Materials using the Group Method

The article deals with the methods of identifying fast neutron age in sodium (Na) and uranium-238 (238U); describes the model of advanced and effective fast neutron nuclear reactors (FN), where Na is a coolant while 238U is involved in the fuel cycle in large quantities; justifies the choice of the group method for calculating the neutron age value in the substances mentioned above that can show the accuracy of the used constants for Na and estimate various versions of multilevel description of neutron moderation in 238U – the most powerful resonance absorber of the neutron reactor active zone

Novel Lyssaviruses Isolated from Bats in Russia

Two new rabies-related viruses were discovered in Russia during 2002. Viruses were isolated from bats in Eastern Siberia near Baikal Lake and in the western Caucasus Mountains. After preliminary antigenic and genetic characterization, we found that both viruses should be considered as new putative lyssavirus genotypes

Substructure depletion in the Milky Way halo by the disk

We employ numerical simulations and simple analytical estimates to argue that dark matter substructures orbiting in the inner regions of the Galaxy can be efficiently destroyed by disk shocking, a dynamical process known to affect globular star clusters. We carry out a set of fiducial high-resolution collisionless simulations in which we adiabatically grow a disk, allowing us to examine the impact of the disk on the substructure abundance. We also track the orbits of dark matter satellites in the high-resolution Aquarius simulations and analytically estimate the cumulative halo and disk shocking effect. Our calculations indicate that the presence of a disk with only 10% of the total Milky Way mass can significantly alter the mass function of substructures in the inner parts of halos. This has important implications especially for the relatively small number of satellites seen within ~30 kpc of the Milky Way center, where disk shocking is expected to reduce the substructure abundance by a factor of ~2 at 10^9 M$_{\odot}$ and ~3 at 10^7 M$_{\odot}$. The most massive subhalos with 10^10 M$_{\odot}$ survive even in the presence of the disk. This suggests that there is no inner missing satellite problem, and calls into question whether these substructures can produce transient features in disks, like multi-armed spiral patterns. Also, the depletion of dark matter substructures through shocking on the baryonic structures of the disk and central bulge may aggravate the problem to fully account for the observed flux anomalies in gravitational lens systems, and significantly reduces the dark matter annihilation signal expected from nearby substructures in the inner halo.Comment: 10 pages, 9 figures, minor corrections, accepted by Ap

RELATION OF IDENTITY AND SUBJECTIVE PICTURE OF THE COURSE OF LIFE OF THE PERSONALITY AT TEENAGERS AND YOUNG MEN

Анализируется проблема связи идентичности и субъективной картины жизненного пути личности у испытуемых подросткового и юношеского возрастов. В ходе теоретического анализа проблемы как отечественных (Е.В. Кулеш, И.А. Буровихина, Е.М. Вечканова) так и зарубежных источников, авторы приходят к выводу, что характер связи идентичности и субъективной картины жизненного пути у испытуемых различного возраста остается дискуссионным. При помощи методик Life Line А. Кроника, СЭИ-тест Е.Л. Солдатовой и Семантический дифференциал на выборке в 150 испытуемых проводится эмпирическое исследование. В результате авторами установлено, что существует специфическая связь между идентичностью и картиной жизненного пути, различная у подростков и испытуемых юношеского возраста. Чем выше испытуемые юношеского возраста оценивают себя по шкалам методики Семантический дифференциал, тем меньше они уделяют внимание своему прошлому.В целом, для испытуемых, переживающих кризисные этапы становления идентичности имеющих низкий уровень самооценки характерно внимание к своему прошлому. Наоборот, для испытуемых со зрелой идентичностью характерно внимание к своему будущему.The article analyzes the problem of relation between identity and subjective picture of a personality’s life line in subjects -adolescents and young people. In the course of theoretical analysis of the problem in native (Kulesh, Burovihina, Vechkanova) and foreign sources the authors come to the conclusion that the type of the relation between identity and subjective picture of life line in the subjects of different age remains debatable. The empiric research was conducted on the sample of 150 subjects with the help of LifeLine by Cronic, SJeI-test bt Soldatova and Semantic differential methods. As a result the authors found out that there exists specific relation between identity and life line picture different in adolescents and young people. The higher the subjects-young people esteem themselves on the scales of Semantic differential method, the less attention they pay to their past. In general, it is typical for the subjects undergoing the crisis stages of identity forming and having low self-esteem to direct much attention to their past. And on the contrary, the subjects with mature, formed identity typically pay attention to their future

Novel strong tissue specific promoter for gene expression in human germ cells

<p>Abstract</p> <p>Background</p> <p>Tissue specific promoters may be utilized for a variety of applications, including programmed gene expression in cell types, tissues and organs of interest, for developing different cell culture models or for use in gene therapy. We report a novel, tissue-specific promoter that was identified and engineered from the native upstream regulatory region of the human gene <it>NDUFV1 </it>containing an endogenous retroviral sequence.</p> <p>Results</p> <p>Among seven established human cell lines and five primary cultures, this modified <it>NDUFV1 </it>upstream sequence (mNUS) was active only in human undifferentiated germ-derived cells (lines Tera-1 and EP2102), where it demonstrated high promoter activity (~twice greater than that of the SV40 early promoter, and comparable to the routinely used cytomegaloviral promoter). To investigate the potential applicability of the mNUS promoter for biotechnological needs, a construct carrying a recombinant cytosine deaminase (RCD) suicide gene under the control of mNUS was tested in cell lines of different tissue origin. High cytotoxic effect of RCD with a cell-death rate ~60% was observed only in germ-derived cells (Tera-1), whereas no effect was seen in a somatic, kidney-derived control cell line (HEK293). In further experiments, we tested mNUS-driven expression of a hyperactive <it>Sleeping Beauty </it>transposase (SB100X). The mNUS-SB100X construct mediated stable transgene insertions exclusively in germ-derived cells, thereby providing further evidence of tissue-specificity of the mNUS promoter.</p> <p>Conclusions</p> <p>We conclude that mNUS may be used as an efficient promoter for tissue-specific gene expression in human germ-derived cells in many applications. Our data also suggest that the 91 bp-long sequence located exactly upstream <it>NDUFV1 </it>transcriptional start site plays a crucial role in the activity of this gene promoter <it>in vitro </it>in the majority of tested cell types (10/12), and an important role - in the rest two cell lines.</p