168 research outputs found

    Orbitofrontal cortex and learning predictions of state transitions

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    Comparative Analysis of Approaches and Treatment Results of Patients with Early and Nonearly Rheumatoid Arthritis

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    The article presents the results of a comparative analysis of different therapy regimens impact on the effectiveness of treatment of patients with early and late rheumatoid arthritis in steady-state. Data on ongoing basis anti-inflammatory therapy of rheumatoid arthritis and the treatment of associated conditions were obtained by continuous copying from case histories of hospital department patients. The observations lasted 12 months. The activity of rheumatoid arthritis before and after the treatment was determined by the DAS 28 (Disease Activity Score) index. The treatment results were evaluated as per the laboratory research and the DAS 28 index, including the counting of painful and swollen joints, erythrocyte sedimentation rate, and health assessment of the patient on a visual analogue scale

    Enhancement of nematic order and global phase diagram of a lattice model for coupled nematic systems

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    We use an infinite-range Maier-Saupe model, with two sets of local quadrupolar variables and restricted orientations, to investigate the global phase diagram of a coupled system of two nematic subsystems. The free energy and the equations of state are exactly calculated by standard techniques of statistical mechanics. The nematic-isotropic transition temperature of system A increases with both the interaction energy among mesogens of system B, and the two-subsystem coupling JJ. This enhancement of the nematic phase is manifested in a global phase diagram in terms of the interaction parameters and the temperature TT. We make some comments on the connections of these results with experimental findings for a system of diluted ferroelectric nanoparticles embedded in a nematic liquid-crystalline environment.Comment: 11 pages, 3 figures, to appear in Volume 42 of the Brazilian Journal of Physic

    Perspectives of using sodium alginate with different molecular weight in the complex cancer therapy

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    The article presents the results of screening research of influence of sodium alginate with different molecular weight on the development of transplantable tumor in mice and the effectiveness of cytostatic treatment. It was determined that sodium alginates with both high (М = 403 kDa) and low (M = 1-10 kDa and M = 1 kDa) molecular weight suppress growth of Ehrlich ascites carcinoma; using sodium alginate (M = 20-30 kDa) in the scheme of chemotherapy increases effectiveness of treatment. Alginates with low molecular weight arrest development of dissemination of Lewis lung carcinoma and sodium alginates (M = 403 kDa and M = 20-30 kDa) in combination with cyclophosphan increase its antimetastatic effect

    Regularities of structural-cellular structure of ovaries in ontogenesis

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    The article presents the examination of the ovaries of embryos, ovaries of human feti and ovaries of children of the tender age. The researches revealed the increase of the surface of follicles, nucleus and primary oocyte's cytoplasm that tells about the fact that further follicular maturation continues in the ovaries of a child of 2-4 months old. Also we registered the increase of nuclear cytoplasmic ratio, appearance of single mature follicles with cumulus oophorus that testifies to the fact that the ovary is functionally mature. Furthermore the research revealed increased content of lipids and DNA in follicular epithelium that also tells aboutfunctional maturity of the ovary. It was found that incretory activity of an ovary during the first year of life is provided by the cells originated from the connective tissue membrane of atresic follicles

    BORIS/CTCFL-mediated transcriptional regulation of the hTERT telomerase gene in testicular and ovarian tumor cells

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    Telomerase activity, not detectable in somatic cells but frequently activated during carcinogenesis, confers immortality to tumors. Mechanisms governing expression of the catalytic subunit hTERT, the limiting factor for telomerase activity, still remain unclear. We previously proposed a model in which the binding of the transcription factor CTCF to the two first exons of hTERT results in transcriptional inhibition in normal cells. This inhibition is abrogated, however, by methylation of CTCF binding sites in 85% of tumors. Here, we showed that hTERT was unmethylated in testicular and ovarian tumors and in derivative cell lines. We demonstrated that CTCF and its paralogue, BORIS/CTCFL, were both present in the nucleus of the same cancer cells and bound to the first exon of hTERT in vivo. Moreover, exogenous BORIS expression in normal BORIS-negative cells was sufficient to activate hTERT transcription with an increasing number of cell passages. Thus, expression of BORIS was sufficient to allow hTERT transcription in normal cells and to counteract the inhibitory effect of CTCF in testicular and ovarian tumor cells. These results define an important contribution of BORIS to immortalization during tumorigenesis

    Adipose-Derived Stem Cells Stimulate Regeneration of Peripheral Nerves: BDNF Secreted by These Cells Promotes Nerve Healing and Axon Growth De Novo

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    Transplantation of adipose-derived mesenchymal stem cells (ASCs) induces tissue regeneration by accelerating the growth of blood vessels and nerve. However, mechanisms by which they accelerate the growth of nerve fibers are only partially understood. We used transplantation of ASCs with subcutaneous matrigel implants (well-known in vivo model of angiogenesis) and model of mice limb reinnervation to check the influence of ASC on nerve growth. Here we show that ASCs stimulate the regeneration of nerves in innervated mice's limbs and induce axon growth in subcutaneous matrigel implants. To investigate the mechanism of this action we analyzed different properties of these cells and showed that they express numerous genes of neurotrophins and extracellular matrix proteins required for the nerve growth and myelination. Induction of neural differentiation of ASCs enhances production of brain-derived neurotrophic factor (BDNF) as well as ability of these cells to induce nerve fiber growth. BDNF neutralizing antibodies abrogated the stimulatory effects of ASCs on the growth of nerve sprouts. These data suggest that ASCs induce nerve repair and growth via BDNF production. This stimulatory effect can be further enhanced by culturing the cells in neural differentiation medium prior to transplantation

    Investigation the structure and properties of deformed semi-finished products produced from chips of Al–Mg alloys system alloyed with scandium

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    The article presents the results of studies that make it possible to solve the problem of processing secondary waste from expensive aluminum alloys without irretrievable loss of metal. For this purpose, tasks were set and solved for the development of technological schemes for obtaining longish deformed semi-finished products from chip waste of Al–Mg alloys 01570 and 1580 alloyed with scandium using methods of powder metallurgy and metal forming. For their experimental verification, the operations of chip briquetting, combined rolling-extrusion (continuous extrusion), sectional rolling, hot extrusion and drawing in combination with heat treatment were applied. According to these schemes, semi-finished products in the form of rods and wires were obtained. Structure and mechanical properties were investigated. It has been revealed that when hot-extruded rods are obtained from chip briquettes of alloy 01570 on a vertical hydraulic press, even with significant degrees of deformation during extrusion, the margin of plastic properties is small and makes it possible to obtain a wire with a diameter of only 4.2 mm after drawing. The processing of briquettes from 1580 alloy chips using the combined rolling-extrusion method makes it possible to obtain after cold deformation a wire with a diameter of up to 3 mm. At the same time, the influence of the annealing process on the structure and properties of deformed semi-finished products from the investigated alloys was studied. It is shown that due to the low plasticity of the investigated material cold working of the rods must be carried out with small degrees of deformation, alternating it with intermediate annealing according to the proposed regime. An analysis of the physical and mechanical properties of the wire obtained using combined processing showed that its strength and plastic properties are comparable to the properties of the wire obtained from a cast billet, and the structure is characterized by a high degree of elaboration and compactness. Thus, as a result of the research, technological schemes have been developed and processing parameters have been determined for the production of rods and wire from graded chip waste of alloys 01570 and 1580 using compaction, discrete and continuous extrusion, as well as cold drawing. © 2022 The AuthorsMinistry of Education and Science of the Russian Federation, Minobrnauka: FSRZ-2020-0013The research was carried out within the framework of the state assignment of the Ministry of Science and Higher Education of the Russian Federation (scientific theme code FSRZ-2020-0013)

    Bacterial diversity in snow on North Pole ice floes

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    The microbial abundance and diversity in snow on ice floes at three sites near the North Pole was assessed using quantitative PCR and 454 pyrosequencing. Abundance of 16S rRNA genes in the samples ranged between 43 and 248 gene copies per millilitre of melted snow. A total of 291,331 sequences were obtained through 454 pyrosequencing of 16S rRNA genes, resulting in 984 OTUs at 97 % identity. Two sites were dominated by Cyanobacteria (72 and 61 %, respectively), including chloroplasts. The third site differed by consisting of 95 % Proteobacteria. Principal component analysis showed that the three sites clustered together when compared to the underlying environments of sea ice and ocean water. The Shannon indices ranged from 2.226 to 3.758, and the Chao1 indices showed species richness between 293 and 353 for the three samples. The relatively low abundances and diversity found in the samples indicate a lower rate of microbial input to this snow habitat compared to snow in the proximity of terrestrial and anthropogenic sources of microorganisms. The differences in species composition and diversity between the sites show that apparently similar snow habitats contain a large variation in biodiversity, although the differences were smaller than the differences to the underlying environment. The results support the idea that a globally distributed community exists in snow and that the global snow community can in part be attributed to microbial input from the atmosphere. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00792-014-0660-y) contains supplementary material, which is available to authorized users

    DNA Methyltransferase Controls Stem Cell Aging by Regulating BMI1 and EZH2 through MicroRNAs

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    Epigenetic regulation of gene expression is well known mechanism that regulates cellular senescence of cancer cells. Here we show that inhibition of DNA methyltransferases (DNMTs) with 5-azacytidine (5-AzaC) or with specific small interfering RNA (siRNA) against DNMT1 and 3b induced the cellular senescence of human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs) and increased p16INK4A and p21CIP1/WAF1 expression. DNMT inhibition changed histone marks into the active forms and decreased the methylation of CpG islands in the p16INK4A and p21CIP1/WAF1 promoter regions. Enrichment of EZH2, the key factor that methylates histone H3 lysine 9 and 27 residues, was decreased on the p16INK4A and p21CIP1/WAF1 promoter regions. We found that DNMT inhibition decreased expression levels of Polycomb-group (PcG) proteins and increased expression of microRNAs (miRNAs), which target PcG proteins. Decreased CpG island methylation and increased levels of active histone marks at genomic regions encoding miRNAs were observed after 5-AzaC treatment. Taken together, DNMTs have a critical role in regulating the cellular senescence of hUCB-MSCs through controlling not only the DNA methylation status but also active/inactive histone marks at genomic regions of PcG-targeting miRNAs and p16INK4A and p21CIP1/WAF1 promoter regions
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