1,129 research outputs found

    Role of structural defects on exchange bias in the epitaxial CoO/Co system

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    We have studied the influence of non-magnetic defects throughout the antiferromagnet Co_{1-y}O on the exchange bias (EB) in epitaxially grown Co_{1-y}O/Co bilayers. These defects are either substitutional or structural (twin boundaries and surface morphology) which both lead to an increase of the EB-field. We find a dominance of twin boundaries over surface morphology (roughness) in enhancing EB which is consistent with the domain state model for exchange bias. In contrast, the crystal orientation of the Co_{1-y}O layer does not show a significant effect on the EB in this system.Comment: 10 pages, 2 figure

    Core promoter short tandem repeats as evolutionary switch codes for primate speciation

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    Alteration in gene expression levels underlies many of the phenotypic differences across species. Because of their highly mutable nature, proximity to the +1 transcription start site (TSS), and the emerging evidence of functional impact on gene expression, core promoter short tandem repeats (STRs) may be considered an ideal source of variation across species. In a genome-scale analysis of the entire Homo sapiens protein-coding genes, we have previously identified core promoters with at least one STR of ≥6-repeats, with possible selective advantage in this species. In the current study, we performed reverse analysis of the entire Homo sapiens orthologous genes in mouse in the Ensembl database, in order to identify conserved STRs that have shrunk as an evolutionary advantage to humans. Two protocols were used to minimize ascertainment bias. Firstly, two species sharing a more recent ancestor with Homo sapiens (i.e. Pan troglodytes and Gorilla gorilla gorilla) were also included in the study. Secondly, four non-primate species encompassing the major orders across Mammals, including Scandentia, Laurasiatheria, Afrotheria, and Xenarthra were analyzed as out-groups. We introduce STR evolutionary events specifically identical in primates (i.e. Homo sapiens, Pan troglodytes, and Gorilla gorilla gorilla) vs. non-primate out-groups. The average frequency of the identically shared STR motifs across those primates ranged between 0.00005 and 0.06. The identified genes are involved in important evolutionary and developmental processes, such as normal craniofacial development (TFAP2B), regulation of cell shape (PALMD), learning and long-term memory (RGS14), nervous system development (GFRA2), embryonic limb morphogenesis (PBX2), and forebrain development (APAF1). We provide evidence of core promoter STRs as evolutionary switch codes for primate speciation, and the first instance of identity-by-descent for those motifs at the interspecies level. © 2014 Wiley Periodicals, Inc

    Peanut consumption and cardiovascular risk

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    Objective We evaluated the effects of peanut consumption on lipid profiles, atherogenic index of plasma (AIP) and CHD risk in hypercholesterolaemic men.Design Randomised crossover clinical trial.Setting Participants were randomly assigned to two groups. They were asked to consume peanut supplements (about 77 g) with their habitual diet for 4 weeks.Subjects Fifty-four hypercholesterolaemic men with total cholesterol (TC) concentrations between 200 and 350 mg/dl.Results Compared with the habitual diet, peanut supplementation of the habitual diet significantly reduced TC/HDL cholesterol (HDL-C) ratio (mean 1 (se 03) P = 0001) and LDL cholesterol (LDL-C)/HDL-C ratio (mean 07 (se 02); P = 0001). Peanut consumption increased HDL-C (mean 61 (se 15) mg/dl; P < 0001) and total antioxidant capacity (TAC) (mean 12 (se 06) U/mL P = 004). In addition, peanut consumption significantly reduced the AIP (mean 01 (se 003) P = 001) and CHD estimated risk over 10 years based on systolic and diastolic blood pressures (mean 14 (se 05 ) P = 0004 and mean 22 (se 05 ) P < 0001, respectively).Conclusions Short-term peanut consumption might improve lipid profiles, the AIP and CHD risk in free-living hypercholesterolaemic men. © 2009 The Authors

    Preliminary Experimental Investigation on a Low Profile Magneto-Hydrodynamic Propulsive Blanket, Considering Plasma Generation

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    The use of magnetohydrodynamic (MHD) blanket propulsion system in ships, even with low efficiencies, has particular benefits that can make them an appropriate option for the marine designers. Accordingly, any attempt to increase the efficiency of these systems requires full recognition of their performance in different conditions. In the present study, as a continuation of previous numerical works by the current authors, a magneto-hydrodynamic blanket propulsion system has been built and experimentally studied through examining the MHD forces produced in different voltages. Copper and gold have been used and compared as electrodes and the high advantage of gold has been demonstrated. The effect of electrolysis on the behavior of the blanket is analyzed. It has been demonstrated that although electrolysis restricts high currents in lower voltages (lower than ~140V) and the saturation of hydrogen decreases the MHD forces due to low electrical current (~140V up to ~160V), the saturation of hydrogen around cathode at high voltages (more than ~160V), makes a dielectric barrier which soon breaks down and make the production of plasma possible, which in turn highly increases the thrust force of the MHD blanket. Therefore, three regimes have been introduced and described for the MHD blanket; the electrolysis regime, the transition regime, and the hot plasma regime. Based on the obtained results, one may conclude that the present results have offered good evidence about the possibility of increasing the MHD blanket performance through plasma production in water
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