559 research outputs found

    Spin-transfer mechanism of ferromagnetism in polymerized fullerenes: AbinitioAb initio calculations

    Full text link
    A mechanism of the high temperature ferromagnetism in polymerized fullerenes is suggested. It is assumed that some of the C60_{60} molecules in the crystal become magnetically active due to spin and charge transfer from the paramagnetic impurities (atoms or groups), such as hydrogen, fluorine, hydroxyl group OH, amino group NH2_2, or methyl group CH3_3, dispersed in the fullerene matrix. The exchange interaction between the spins localized on the magnetically active fullerenes is evaluated using \textit{ab initio} calculations. The nearest neighbour and next nearest neighbour exchange interaction is found to be in the range 0.1÷0.30.1\div 0.3 eV, that is, high enough to account for the room temperature ferromagnetism.Comment: typos corrected, 8 pages, 3 figures, LaTe

    The Homogeneous Catalog of the Main Parameters of Open Star Clusters

    Full text link
    A brief summary of the updated catalog of homogeneously estimated reddenings, distances from the Sun and ages for 367 open star clusters is given

    New Advantageous Method for the Production of Purified Cholera Toxin B-Subunit and Monoclonal Antibodies to It

    Get PDF
    Put forward is an efficient method for manufacturing cholera toxin B-subunit. Its advantages are relative simplicity and economy feasibility, as well as maximum output of the purified B-subunit, absolutely free from toxic A-subunit contaminant. All this is due to the deployment of cholera vibrio recombinant strain producing only cholera toxin B-subunit instead of cholera toxin as it is, which results in lack of residual preparation toxicity. Applied has been gel-penetration column chromatography, providing for stable native state and maximum antigen output. The method under discussion is verified experimentally. Sample purity has been analyzed after each phase of chromatographic investigation on TSK gel HW-60, using disc electrophoresis. It is established that three steps of purification are ample for the obtainment of cholera toxin B-subunit preparation free from admixtures. Immunological activity of the purified B-subunit is validated by monoclonal antibody obtainment. Designed preparation of cholera toxin B-subunit and monoclonal antibodies to it can serve as a basis for the development of various immune-diagnostic test-systems alternatives

    SiC Nanofibers in Canals and Pores of Cordierite Honeycomb Material as a Support for Catalyst in CO-PROX Reaction

    Get PDF
    The Cu–Co oxide system supported on SiC nanofibers deposited on cordierite was studied in the CO oxidation reaction in the presence of hydrogen

    Effect of antibodies to glutamate on age-related memory changes in C57Bl/6 mice

    Get PDF
    Chronic intranasal administration of antibodies to glutamate to aging C57Bl/6 mice improved passive avoidance conditioning, had no effect on horizontal and vertical locomotor activity, but slowed locomotion in the open-field test. Administration of antibodies to glutamate increased the content of dopamine and its metabolites in mouse hippocampus, but had no effect on the metabolism of neurotransmitter amino acids. In the frontal cortex, antibodies to glutamate did not affect neurotransmitter metabolism, but increased the level of both excitatory and inhibitory amino acids without changing their ratio

    New antiretroviral agent use affects prevalence of HIV drug resistance in clinical care populations

    Get PDF
    OBJECTIVE: To estimate the prevalence of HIV drug resistance over time and identify risk factors for multiclass resistance. DESIGN: Prospective clinical cohort of HIV-infected patients at the University of North Carolina. METHODS: Among antiretroviral therapy (ART)-experienced patients in care 2000-2016, we estimated annual prevalences of cumulative resistance, defined as at least one major mutation by drug class. Clinical data and multiple imputation were used when genotypic data were missing, and mutations were carried forward in time. We estimated resistance odds ratios comparing characteristics of patients in care in 2016. RESULTS: A total of 3682 patients contributed 23 169 person-years. Prevalence of at least one major resistance mutation, irrespective of viral suppression, peaked in 2005 with 49% (95% confidence interval 46, 52) and decreased to 38% (35, 40) in 2016. Resistance to nucleoside reverse transcriptase inhibitors, protease inhibitors, and nonnucleoside reverse transcriptase inhibitors also peaked in 2005-2007 and decreased to 28 (26, 31), 14 (12, 16), and 27% (24, 29) in 2016, respectively. In 2016, prevalence of integrase strand transfer inhibitor (INSTI) resistance was 2% (1, 3) and triple-class resistance 10% (9, 12). Over the study period, cumulative resistance was frequent among patients with detectable viremia, but uncommon among patients initiating ART post-2007. Among 1553 patients in care in 2016, ART initiation at an older age, with an INSTI, and with higher CD4 cell counts were associated with resistance to fewer or no classes. CONCLUSION: Prevalence of resistance to older ART classes has decreased in the last 10 years in this clinical cohort, whereas INSTI resistance has increased but remained very low. Patients with viremia continue to have a high burden of resistance even if they initiated ART recently

    Lipoplexes of dicationic gemini surfactants with DNA: Structural features of DNA compaction and transfection efficiency

    Get PDF
    © 2015, Pleiades Publishing, Ltd. The internal structure of DNA lipoplexes with hydroxyethylated alkylammonium gemini surfactants (GS) with high transfection activity was studied by circular dichroism. It was shown that the efficiency of transfection of HEK293T cells with the pEGFP-N1 circular plasmid was different from zero only in the region of existence of chiral supramolecular DNA-GS complexes and reaches a maximum at concentrations at which the spontaneous aggregation of components is observed

    Complexes of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with transition metal nitrates. Micelle-forming, solubilizing, and adsorption properties

    Get PDF
    © 2017, Pleiades Publishing, Ltd. Amphiphilic complexes of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide (D-16) with nitrates of transition metals (La 3+ , Cu 2+ , Ni 2+ , and Co 2+ ) have been synthesized and characterized. Absorption spectrophotometry in the UV, visible, and IR regions, as well as 1 Н NMR spectroscopy, have been employed to study their spectral properties in water and organic media. Adsorption properties and micelleforming and solubilizing abilities of the amphiphilic complexes have been investigated in aqueous solutions by the methods of tensiometry and conductometry, as well as by solubilization of a water-insoluble dye (Orange OT). The values of the critical micelle concentration, adsorption parameters at a water/air interface, and solubilization capacity S of complex micelles have been determined. It has been shown that the most pronounced decrease in the critical micelle concentration (as large as two to three times) and differences in the adsorption characteristics and the S values as compared with those of ligand D-16 are observed for complexes of copper and lanthanum. The S values for these complexes are 1.3−2.5 and 3−6.5 times higher than those for D-16 and cetyltrimethylammonium bromide, respectively

    Chronic kidney disease (CKD) in disadvantaged populations

    Get PDF
    Twelve March 2015 will mark the 10th anniversary of World Kidney Day (WKD), an initiative of the International Society of Nephrology and the International Federation of Kidney Foundations. Since its inception in 2006, WKD has become the most successful effort ever mounted to raise awareness among decision-makers and the general public about the importance of kidney disease. Each year WKD reminds us that kidney disease is common, harmful and treatable. The focus of WKD 2015 is on chronic kidney disease (CKD) in disadvantaged populations. This article reviews the key links between poverty and CKD and the consequent implications for the prevention of kidney disease and the care of kidney patients in these populations

    The transition between stochastic and deterministic behavior in an excitable gene circuit

    Get PDF
    We explore the connection between a stochastic simulation model and an ordinary differential equations (ODEs) model of the dynamics of an excitable gene circuit that exhibits noise-induced oscillations. Near a bifurcation point in the ODE model, the stochastic simulation model yields behavior dramatically different from that predicted by the ODE model. We analyze how that behavior depends on the gene copy number and find very slow convergence to the large number limit near the bifurcation point. The implications for understanding the dynamics of gene circuits and other birth-death dynamical systems with small numbers of constituents are discussed.Comment: PLoS ONE: Research Article, published 11 Apr 201
    corecore