In black south africans from rural and urban communities, the 4G/5G PAI-1 polymorphism influences PAI-1 activity, but not plasma clot lysis time

Data on genetic and environmental factors influencing PAI-1 levels and their consequent effect on clot lysis in black African populations are limited. We identified polymorphisms in the promoter area of the PAI-1 gene and determined their influence on PAI-1act levels and plasma clot lysis time (CLT). We also describe gene-environment interactions and the effect of urbanisation. Data from 2010 apparently healthy urban and rural black participants from the South African arm of the PURE study were cross-sectionally analysed. The 5G allele frequency of the 4G/5G polymorphism was 0.85. PAI-1act increased across genotypes in the urban subgroup (p = 0.009) but not significantly in the rural subgroup, while CLT did not differ across genotypes. Significant interaction terms were found between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. The C428T and G429A polymorphisms did not show direct relationships with PAI-1act or CLT but they did influence the association of other environmental factors with PAI-1 act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. In conclusion, although the 4G/5G polymorphism significantly affected PAI-1act, it contributed less than 1% to the PAI-1 act variance. (Central) obesity was the biggest contributor to PAI-1act variance (12.5%). Urbanisation significantly influenced the effect of the 4G/5G polymorphism on PAI-1act as well as gene-environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT

Rosuvastatin use increases plasma fibrinolytic potential: a randomised clinical trial

We conducted a study to assess the effect of rosuvastatin use on fibrinolysis in patients with previous venous thromboembolism (VTE). This was a post hoc analysis within the STAtins Reduce Thrombophilia (START) study (NCT01613794). Plasma fibrinolytic potential, fibrinogen, plasmin inhibitor, plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (

Neel vector reorientation in ferromagnetic/antiferromagnetic complex oxide nanostructures

In this study, we report on a temperature-driven antiferromagnetic (AF) spin reorientation transition in micro- and nanostructures of AF/ferromagnetic (FM) LaFeO3/La0.7Sr0.3MnO3 thin film bilayers. Using a combination of x-ray photoemission electron microscopy and x-ray absorption spectroscopy, the Néel vector is shown to reorient 90° as a result of the competition between a shape-imposed anisotropy in the AF layer and interface coupling to the adjacent FM layer. We demonstrate how a temperature dependence of the AF/FM spin configuration in line-shaped nanomagnets can be tuned by variation of their linewidth. This work provides insight into the AF/FM interface exchange coupling in complex oxide heterostructures and the possibilities of spin control by nanostructuring in thin film spintronics

Effects of array shape and disk ellipticity in dipolar-coupled magnetic metamaterials

Two-dimensional lattices of dipolar-coupled thin film ferromagnetic nanodisks give rise to emergent superferromagnetic (SFM) order when the spacing between dots becomes sufficiently small. In this paper, we define micron-sized arrays of permalloy nanodisks arranged on a hexagonal lattice. The arrays were shaped as hexagons, squares, and rectangles to investigate finite-size effects in the SFM domain structure for such arrays. The resulting domain patterns were examined using x-ray magnetic circular dichroism photoemission electron microscopy. At room temperature, we find these SFM metamaterials to be below their blocking temperature. Distinct differences were found in the magnetic switching characteristics of horizontally and vertically oriented rectangular arrays. The results are corroborated by micromagnetic simulations

Magnetic domain formation in ultrathin complex oxide ferromagnetic/antiferromagnetic bilayers

In this study, we report on the magnetic domain formation in ultrathin blanket films and patterned micro- and nanostructures of ferromagnetic (FM) La0.7Sr0.3MnO3 single-layers and antiferromagnetic (AF)/ferromagnetic LaFeO3/La0.7Sr0.3MnO3 bilayers, as investigated by soft x-ray photoemission electron microscopy. In single-layer La0.7Sr0.3MnO3, the domain size is significantly reduced compared to that found in thicker layers, and rectangular micromagnets display metastable multidomain states distinctly different from the flux-closure ground states commonly found in thicker elements. In the LaFeO3/La0.7Sr0.3MnO3bilayers, complex multidomain patterns are observed for blanket films and patterned magnets with robust perpendicular (spin-flop) coupling between spins in the AF and FM layers. By thermal cycling of the sample through the La0.7Sr0.3MnO3 Curie temperature, we find that the native antiferromagnetic domain pattern of LaFeO3 pins the location of domain boundaries in the adjacent La0.7Sr0.3MnO3 layer

Effects of lattice geometry on the dynamic properties of dipolar-coupled magnetic nanodisk arrays

We have studied the impact of lattice geometry on the dynamic properties of close-spaced arrays of circular nanomagnets, also known as magnonic crystals. To this end, we prepared 2D nanomagnet arrays with both square and hexagonal lattice symmetries (300-nm disk diameter, 400-nm center-to-center distance) and performed broadband ferromagnetic resonance (FMR) measurements. Micromagnetic simulations were used to interpret distinct features of the measured resonance spectra. The FMR bias field was applied along two distinct principal directions for each lattice, and a sample with well-separated, decoupled disks was measured for reference. We found that the interdisk dipolar coupling has a strong impact on the FMR for these 2D magnonic crystals. Distinctly different oscillation modes were found for the individual nanomagnets, dependent on lattice symmetry and direction of the bias field. Moreover, we find that spectral peak splitting from excitation of edge and center modes, as well as the damping, depends on the lattice symmetry and the orientation of the bias field. These findings demonstrate that lattice geometry has a strong influence on the excited spin-wave spectrum and is a relevant design parameter for spintronic devices